The above shell is a copy of Don's watercolor painting of The Nautilus shell; it is Don's logo. The shell is beautiful,  its shape a mathematical curve, and can be obtained from conchking. Also see the equation for the shellmaking a spiral , IES java applet making a Nautilus, Xah Lee's work on spirals (and other curves) and student work on the growth of the Nautilus (chapter 6), and Don compares the Spirals of the Nautilus shell, the Fibonacci numbers, and the Equal Tempered Chromatic Music Scale .

Don retired from The Math Program

as of May 30, 2014

Don's new telephone #  is 217.840.4559, same email address:

Don's new address: 1905 S. Prairie Winds Dr. Apt. 204, Urbana, IL 61802

On the last day of the school year 2013-2014, Sue, below, received an award for the most improved math student in 5th grade at Holy Cross elementary school. Read what Grandma had to say!

                            Meredith was given this award from her HS math teacher. Don tutored Meredith during the 2013-2014 school year-- 2x/week. It's great when his students get awards.
Don's DVD is all electrononic delivery

the new ies applets URL in Japan is

Do you understand? Don asks his students- in different languages!


 Refreshing insights into the learning and doing of some important mathematics, by young people (while doing lots of arithmetic, using many hands-on materials, science to math activities, and the non-trivial use of calculators and computers)-- for children, as well as adults Don assumes only that a student can count.

Don's keys:


look for patterns,

learn to learn

 On Don's Teaching

Don had Sheri as a 4-6th grader; then she went to University High School. She came back as a 12th grader, in the Summer of 2008, to prepare for Calculus. Don worked with her for 3 weeks before school started. A week into her calculus class, she told Don- "What we did the last 3 weeks (derivatives), the teacher did with my class in one day, and I was like the only one in the class that understood what she was talking about! It really helped for me to talk with you about the problems as I worked on them"
It's been a pleasure working with you Sheri, as well as your sister, your mother, 2 aunts, and 3 cousins over the years- what a wonderful family!

Jonathan, above, at ages 7 and 8, came from Connecticut for a week, each of  2 summers to work with Don. He worked on infinite series, solving quadratic equations (Ch. 8), iteration, ++. He is in Don's videos and in Don's  worksheet book. And he received his Ph.D. in physics!


17 January, 2012

I thought you'd be interested to learn that Charlie has been offered, and has accepted, a three-year post-doctoral appointment at the Institute for the Physics and Mathematics of the Universe (what a title!) of the University of Tokyo in Kashiwa, Japan, beginning sometime this summer. It comes with a terrific salary and benefits, and it was his first choice. We're very proud of him!
He'll get his Ph.D. in Physics in May 2012.


Don now has had 5 students who have received Ph.D.'s in Physics and one a Ph.D. in Mathematics.


"Logic will get you from A to B.

Imagination will take you anywhere".
- Albert Einstein

“If aliens are watching us through telescopes, they’re going to think the dogs are the leaders of the planet. If you see two life forms, one of them is making a poop, the other one’s carrying it for him, who would you assume is in charge?” - Jerry Seinfeld


6 June 2013Don received this email: Hi Mr. Cohen,
I wanted to tell you that I graduated high school last month! I wanted to tell you this because there is no way I would have survived my math classes without you! You were so much help! I even finished my last semester with a B+ in statistics! All of this is thanks to you!
I just felt that I needed to thank you!
Again, I could not have made it without you and I'm forever grateful,
-- L. S.

27 April 2013 A LinkedIn message to Don:

Yes Don - I brought my daughter Natalie to work with you in 2000 and 2001. Natalie is graduating in June with 2 BS degrees, majors in cell biology and math. She is going to attend the graduate program in biomedical informatics at Stanford University. Your work with her was a part of the love for math that I wanted to develop and it worked. [See Natalie's work that she did with don in 2000 ( at age 7) at what she did during the year, until she returned in 2001 (at age 8) at !]

Best wishes,



February 2013- some exciting Guess My Rule games by Sara K,  Maya K, Jack.E, and Ratan - look out!

 Asiya: Hi Mr. Cohen! I just wanted to share with you that I am a Sophomore in a 4 year university this semester and I'm taking 4 math classes and doing okay. I think about your book all the time and your approach to math.
Sent at 9:13 AM on Thursday  Jan.24, 2013
Asiya: You have really inspired me to go beyond the formulas printed on the page and think about math.
I have been told that my mathematical thinking is good, even when my calculations are off.
I got a job as a Math Tutor and am a Math Minor right now, when I complete the Math Minor (18 credits BEYOND calculus 3) then I may, in fact, go for a math major.
I just wanted to share that information with you and let you know how I am doing mathematically and to say THANK YOU!!!
Sent at 9:15 AM on Thursday, Jan.24, 2013 Don sent Asiya his Worksheet book about 4 years ago.

From a parent whose 2 children came to work with Don for a number of years- a great description of Don's teaching::

"Typical approach studies one simple concept at a time- boring- isolated, irrelevant. Instead- have a more interesting, complicated problem, that uses these concepts in finding the answer. This leads the student through math concepts, seeing them in their natural context and usefulness. Also, when the problem is finally solved, the "Look what I can do!" feeling spurs further exploration of math."

15 June 2012 From a parent who just purchased Don's 2 disc set (now 1DVD) with all his materials:

"My children are 12 and 10. They are already in advanced math at their schools, but it was clear to me that they were learning aspects of math without knowing how or why it was useful. I just googled 'how best to explain calculus to kids' and came across your site. I wanted them to see math in a different way than just memorizing and doing worksheets.

Thanks for taking the time to put your set together and doing what you have done".-Sundar R.,

What people are saying about Don's "A Map To Calculus"

To search Don's site, for say "iteration", google  iteration

Translate Don's web pages into your language (also use the translator, the A in the upper right on any of Don's pages).

"Learning, Living and Loving mathematics.."- the core of Don's teaching and books, ;

observed by Seth Nielson (see LOVE YOUR BOOK below).


 Creative Commons License
"Calculus By and For Young People-Worksheets" by Donald Cohen, is now under a CC license . Now it can be used on OLPC computers!.

¡bienvenido a casa!; hoan nghênh; karibu!; aa'o bhagat karna; Willkommen; Selamat Datang; Aapka swagat hai; Sawasdee Krub; kumusta, ; Makati, Phililppines; New Delhi, India; Shinjuku, Japan; La Crosse, WI; Champaign, IL; Gardendale, TX;  2 CD set to Maylasia;  2 CD set to Singapore; Leicester, UK; Bangkok Thailand, 21 visitors/month averaging 1 hr 53 min on Don's site- a record!; London, ON, Canada; ..and all the world.  During 15 Nov.-15 Dec. 2009, at least 1 person came from every state in the US to Don's website; the most came from Illinois with 175. Over 1500 people from 70 countries around the world, came to Don's website, as shown in Google Analytics. 

Click to give free food +, on the Hunger Site.

You can now choose from a topic on Don's A Map to Calculus , click on it, and find  student works and discoveries, and sample problems from Don's books on the topic with the chapter#. Very exciting- Jonathan Storm made it all possible! 

Try sample problems from Don's books,  

by chapter, (chapter #s are also shown on the A Map to Calculus), or click on a topic)..



Exciting news- all the time

5 April 2013Don asked Julia to make up an equation which has NO answer. She gave up quickly, but Don pushed, and this is what happened: images\juliasequations.jpg

26 March 2013 Don, Maya (6th grade), Anleen (11th grade) and Alice (11 grade) are working on Ramanujan's expression for 1/Pi

Very exciting!

16 March 2013  Maya, Sara (2), Jack  and Ratan make up other rules for Donk

29 October 2012 MarieK shares 8 cookies between 3 people to get a division problem 8 divided by 3 = 8/3 (a fraction) = 2 2/3 (a mixed number)= 2.666... (an infinite repeating decimal) = 2 + 6/10 + 6/100 + 6/1000 +   ... (an infinite series) and you could probably write it other ways! .  You can view the video of Don and Marie doing this on youtube at


28 September 2012Don, Shouri (3rd grader), and Grant (HS junior), work on Ramanujan's  Infinite Nested  Square Roots


20 September 2012 Shaleen (age 14), asked: Can we rotate a sine wave 60occw? See how Don, Shaleen and Lori did it!


20 September 2012Zachary's math work with Don this Summer of 2012


21 August 2012  From an email: "Hi Don,

I receive the DVD yesterday. Thank you. I am a high school math teacher and will be teaching calculus this fall. I was searching for materials and I find your material through this link
I look through some of the problems in your book and it emphasizes
critical thinking skills. It is also presented them in a way that students or kids will not be overwhelmed with the math symbols and language.

Thanks for putting up lot of examples of hands on activity on your website. I will probably look through those for ideas too.

Enjoy your summer with your family

From a Facebook note from Barbara Maclay Cameron, a student of Don's from 30 years ago: "It can be hard sometimes to trust that unschooling really works. And then you find yourself having a conversation with your (very excited) children about multiplying positive and negative numbers. I'm not sure I would believe this if it weren't happening right in front of me. — with Donald Cohen and Joanna Hawkins Maclay [Barb's Mom]".

 You can find the postman stories in Robert B. Davis' books online
(Discovery in Mathematics- student guide Or teachers guide) at

From Barb' Mom, Joanna Hawkins Maclay: Oh I miss those wonderful smiling faces! And the postman stories, YES! Thank you Don Cohen. [See Barbara's Facebook page for further discussion].

2 July 2012:Brenda Works on a regular Pentagon

22 May 2012: Email sent to Don almost 20 years ago:Mr. Cohen,

Greetings from Ohio! I’ve always meant to keep in touch but time seems to slip by. Now that I’m ready to graduate I thought I’d drop you a line to tell you how much I appreciate the few years I got to work with you in The Math Program. You instilled a love for math in me that was able to get me through many hours of boring high school math.

I will be graduating June 5th as valedictorian of my class. Through the Academy Program offered by the State of Ohio, I was able to attend the local branch of Ohio State my Jr. and Sr. years and will graduate with 65 hours of college credit.

I am a National Merit Finalist and am attending Ohio State Honors Program on a full academic scholarship.

Even though my math teachers tried to put me down for my odd ways of performing math, I managed a 790 on my Math SAT and am planning on majoring in both Math and Psychology.

I’ve always regretted having to move away from your program but what you gave me really helped mold what I am today.

Many thanks. I’m sure our paths will cross again some day.

Thanks for your inspiration,

Kohler [click on Map at Archimedes to see some of Kohler's work]


18 May 2012From an email: "Hi Don, I found this by accident. Wolfram posted previews to the animations I did of your dog!!!

Short link:".Lori Johnson Morse,

3 May 2012 In an email: "Hi, Don,
I just watched the You Tube video of your James Scholar Award. So amazing!! So well deserved!! You are a true inspiration.
At a time when people do not really know, or care to understand the meaning of the word “hero” or “role model”, you are a testament to what it means to live an engaged, meaningful and inspiring life.
--Jay.- father of 3 of Don's students, one of whom came for 12 years, the other 2 have come for 6 years

29 April, 2012 "Don Cohen, the Mathman, is simply the best educator I have ever met. He taught me more about teaching mathematics and calculus to young people than I have learned from any other person or book. Watching him work with his students is like nothing you've ever seen.

Don is more than an educator to me. His is one of the most generous and kind people I have ever met. He always gives his best to his students and believes in their abilities to learn extraordinary things. I wish all my teachers could have been like him.

Congratulations, Don!" from Lori Johnson Morse, a great friend and great math tutor in K.C., MO

28 April, 2012

       Dear Mr. Cohen,

Thank you so much for the beautiful painting

& for helping me so much with math! I love being

able to save my questions about my homework until

Saturday because I know that I will be able to understand

what I'm doing in class after I leave your house.

Thank you!

Love, E (a HS junior)



 21 April, 2012 Don was asked 2 weeks before, by his son Mark, to join him for lunch Saturday April 21, 2012. Don had to reschedule a group of students, and did so. Mark didn't tell him, nor did anyone else, where the lunch was being held. We ended up at the UI football stadium. [A little behind the scenes action had been going on without Don's knowledge- Associate Dean of Education Chris Span (in charge of the program), 3 weeks before, had signed up his 6 yo son Langston, to work with Don on math, was excited about what he saw, and soon found out Mark's telephone number from his brother. Mark's wife was a UI alum and a James Scholar and they all worked together to get this done. The Dean wanted a member of the community to receive one of the awards and found Don who has been tutoring in the C-U area for about 36 years!] Needless to say it was an exciting & humbling luncheon and Don thanks all the people involved. To see the Don receiving the award from Dean Span go to this youtube link .

16 April, 2012Don worked on this problem with a student in Algebra 2: Simplify (1/27)1/3. We came out with the answer 1/3. Don looked at what we had and immediately asked when will we get the same answer as the original exponent ? The next day he gave the problem to Shaleen, who thought about it for about 2 minutes, and came up with his rule below. After that Don solved the equation: (1/x)(1/y)=1/y

3 April, 2012 , Don received a Facebook message from Maggie Q. "Hello Don! I hope you remember me. I just wanted to send a message to let you know what a positive influence you had on my life growing up.

I just watched a documentary about the Mandelbrot equation, and it reminded me that you always had a picture of it in your basement and would

refer to it occasionally. I never really understood it, but I think I get the basic gist of it now.

While I didn't grow up to be a mathematician or anything like that, you helped me feel more comfortable around tougher conceptual ideas. You always had me doing such cool stuff. It made math seems more accessible to me, and increased my self efficacy and self esteem. The basic understanding has helped me connect with the world and have a better understanding of current events. I ended up going into business, but work on the business and user end of software development, so am around technical people every day. I actually got called back twice for a job at Wolfram Alpha, but eventually decided to move to Vancouver, BC to be with my family.

I have never told you before how much I appreciated your help growing up. It meant a lot to me to have someone on my team and rooting for me. I had a rougher time as a teenager, perhaps because Champaign was so quiet and small, but things have been going really well since then. I try to stay current on math and science events, and am fascinated by all of it, even if I don't fully understand it. I don't know if I can truly express the positive impact that your influence had on me, but I tried! Please take care and I wish for all of the best for you and Marilyn! Regards, Maggie Q"

1 March 2012:

<Take a look at this lesson

that Don does with kids who have worked with exponents, to find 642/3

14 December 2011: Don found the sample problems from chapter 11 of his worksheet book, on the website of NSDL, the National Science Digital Library (search "iteration" or compound interest to E and I).

7 November 2011: In a note from Tammy's greatgrandmother: "Hi Don! Thank you, thank you for instilling the power to learn, to Tammy and the fact she's enjoying it. Enclosed is my check for 10/29-11/28". [Tammy came for one month, twice a week; she is 15 yo, with a weak background in math, but is committed to learning. It's a pleasure to see her confidence grow].

13 September 2011: Sarah's Mom worked with Don ~ about 30 years ago. See what Sarah, age 6, did with Don in 5 days, 2 hours/day, June 29-July 3, 2011.

27 July 2011 email: Don worked individually with Zachary for 2 hours each day, for 5 days.

Dear Mr. Cohen,

Thank your taking your time to teach Zachary last week. I must admit, I enjoyed watching the light bulb go off in his face the many times that it did. Not many teachers have the technique that you use. You do not correct the error in his problem. You correct his thought process and make sure that he understands the issue by solving it many different ways, all hands on. Your course was more that of a mathematics apprenticeship than of a worksheet grind that we are so familiar with. Your one and one teaching challenged him, made him go just a little bit farther and made him excited about math. Again my hat is off to you.


       David K.  (IN) - Zachary's Dad

[David followed up and has brought Zachary back for one weekend (four hours individually with Don) in each of the 4 months, September, October, and November 2011].

11 June 2011- from an unexpected email: An acknowledgement

I think you might enjoy this story: In his astronomy PhD thesis, our older son, Alex, wrote “Mom and Dad (Jan S. and Tim H.), thank you for all the ways you nurtured my curiosity (maybe even including the calculus book in first grade) ….” We didn’t remember giving him any such book, but our younger son, Peter, confirmed the story and said the spiral-bound book had been handed down to him and was still on the bookshelf in his old bedroom. Sure enough, I found there your Calculus By and For Young People! So apparently Alex remembered correctly (or almost correctly—it’s the 1991 edition, and Alex was in first grade in 1988–89).


6 April 2011 The following is an essay that was sent with his college application by an 18 year old:

    I am no dunce at mathematics, yet from the time I was six years old, I have studied with a math tutor named Don Cohen.  Math, while an extremely important skill, is not the most crucial lesson I have learned from him through the years.  Don Cohen, a renowned math teacher and a winner of many teaching awards[2], is known for his unusual approaches to teaching.  My math instruction has been no exception.  I have not memorized a single formula, and instead, I have learned to approach math problems from different perspectives.  Simple lessons that I have learned, such as any problem can be broken down into a simpler form of the same problem, have uses outside the field of mathematics.  I have learned the analytical thinking that is essential to mathematics.  At the same time, this discipline influences my other thought processes to this day.

29 March 2011 From an email: Hi Mr. Cohen,

I wanted to know if you are still teaching. If you are what is the current rate structure of the program? My children have just started school and I wanted to ask what you would recommend as far as getting them started with mathematics. My daughter will be in first grade and my son will be starting Kindergarten in the fall. I would love for them to be able to come and experience the “Mathman” environment. I too was a student of yours and thoroughly enjoyed every minute of it. I would love to come back.


Jennifer W.

Jennifer is the 3rd mother he had long ago, who now sends 2 of her children to Don!

19 March 2011 From an email:

Hi Don!

This is Becky W. - about 30 years ago, you knew and taught me as Becky E.  I'm excited to see that The Math Program is still trucking away after all these years; I know Sheri (my niece) really loved it!

I am writing because my own daughter Sarah is now 6, and I would love for her to meet you and spend a week over the summer in The Math Program while we're out visiting family.  She's doing great at math in school, but the program doesn't spark her imagination or give her the courage to experiment.  Besides, how cool would it be for her to be taught by you?  I'd love to share that with her. there an application process?  Are there better or worse weeks?  It would be in late June or in August; we're booked through July already.

All the best,

The article below describes what Becky (above) did, when she was 8 yo, working with Don at The Math Program. D.S.F. was David S. Fielker, the editor of the Math Teaching (England) journal at the time.

Can you generalize Becky's rule?

6 March 2011: From Don's facebook conversation with Barbara, his student from 31 years ago, about the pyramid her daughter Maggie made.
4 March 2011: I found a formula to find the area of shapes on a geoboard, then graphed it in 2D and 3D; by Irisa, a 6th grader
22 February 2011: Jack, a 4th grader, draws a Penguin & asks Don to help him describe it using the graphs of equations!

February 2011 From a parent and son:

While watching my 26 year old son with Don aka "the mathman" this morning at breakfast, it was de ja vu only with a twist. This morning, Jonathan was going over material and making drawings to illustrate to Don some things that he may not have known instead of Don doing the illustrations and making explanations for him as Don had done many times and many years ago.

You see, Don was highly recommended to me by a very good friend who sent her daughter to him when she struggled with math before becoming a teacher years later.

I called him and explained that my son was 12 and was being made to feel he was stupid in school when it came to math, even though he excelled to a level far beyond most in his class and many other classes above him in every other subject. I knew something was terribly wrong and I had to do everything in my power to prevent his failure, knowing how intelligent he was. I just couldn't seem to help him because he needed to learn math in a different way from the one and only way it was being taught in the schools. I was also taught that one particular way which was why I never excelled in math and really wasn't ever excited about it even to this day.

To make a long story short, a meeting and first 2 hour lesson was set up with "the mathman" and when I dropped my son off, all I could do was pray that this might be the help he needed. Lo and behold, when I picked Jonathan up from his lesson and he got into the car, he excitedly began to tell me about the things he did and learned in that two hours and he never stopped talking about math from that day and couldn't wait to get out of school for the day to get to Mr. Cohen's lessons so he could actually learn something.

You see, Don has a special way of relating to all of his students that gives them self esteem and makes them realize they can not only learn to do math, but they can also enjoy math and do more than they ever dreamed they could, like calculus. He knows not every child learns in only one way and Don lets the students know that that does not make them wrong OR STUPID!

I heard someone ask Don to explain what his method of teaching was. "How do you do what you do with so much success?"

Until I actually observed some of the sessions and could see the excitement of his students including my own child, I couldn't have pinpointed any obvious teaching method per se. I can only say that Don opens the minds of his students and expands their horizons in such a way that is simply unbelievable. My explanation is that it is his personality.

Don can pull things out of the students by getting them to reach far back into their minds and find answers that they never would have considered looking for had they not been sitting beside him. If they come up with a different answer to something, he doesn't tell them they are wrong, he says let's look at this and see how you arrived at that answer.

What a concept! 

Soon, the students are looking at mathematics in an entirely different light and looking to their future in a way that the never could have hoped for before knowing "The Mathman".

Don and his lovely wife Marilyn are known and loved by probably thousands of previous students and will never be forgotten. My son and I will always be thankful and privileged that we met them so many years ago and will always call them friends.

Carol Storm Gudeman and Jonathan Storm

[See Jonathan's calculus way of finding the volume of a cylinder on his blog at

http://www.technicalmisery. com/2011/02/cylinder-fun.html

N.B. The student is much smarter that the teacher now!]

14 January 2011: Ed Cherlin, from OLPC (One Laptop Per Child) asked Don if he was interested in having his calculus for young people materials be part of their 2 million computers under a Creative Commons License. Don has agreed to do this.
17 December 2010, from an email "Hi, Don,

It's Peter Farrell, a math tutor/teacher fan of yours from California. I've gotten an unbelievable amount of inspiration from your works. You have a unique way of making it seem perfectly normal to have little kids playing around with calculus, infinite series and matrices!

I've been acting like a little kid myself, trying to come up with fun ways to teach a short calculus course to homeschoolers next month. I plan to go straight to differential equations, since they're the whole point to learning calculus. I'm planning to use computer applications to circumvent the drudgery of taking derivatives and slogging through the algebra. I learned from you that the majority of the ideas in calculus are immediately accessible.

The attached word doc is an exploration in optimal design I came up with, but your influence is obvious. I wonder if calculus teachers would be interested in an elementary application of differential equations. Any input you have would be greatly appreciated.

Best wishes for the holidays and Happy New Year!

Peter Farrell"

10 December 2010: From Ashley's Mom, describing in part how Don teaches:

"The funny thing about the boy in our carpool was that a few days earlier he had asked Ashley if she knew her multiplication tables, which she does not, although she does know how to do "four fives" and count it up to get the answer. So he was explaining about the nines multiplication facts, and showing her a method of using your fingers to represent ten and then counting starting with your left pinky. Well, Ashley thought that was cool, and the next day she said she wanted to explain a math problem to him. I chuckled to myself as I drove, because I knew what she was going to explain. He kind of brushed her off, and he explained something he had learned in math that day, and when she took her turn explaining how to use bags of washers to solve equations with balance pictures, it really surprised him. He had put her at a certain level because she doesn't yet know the multiplication tables. But when students learn the way that you teach, you are building on whatever they do know and helping them figure out ways to solve problems with what they are already able to do, instead of thinking that someone can't do something because they haven't learned multiplication or division yet" :-)  [ see Balance pictures to solve equations on Don's A Map to Calculus ].

13 November 2010 Don has worked with Sara since she was 5 yo, now 9 yo. He came down to the Mathroom one day to find her writing on the chalkboard:

Do you see why Don loves to teach?

25 October 2010 from a letter: "Hello Don Cohen,

I came across your book "Calculus By and For Young People" in the last few days, after not cracking it for some time. I happened across your note about Judy Silver, [a 1st grade teacher in Don's class for teachers at Webster College, who figured out the relationship between the derivative and the integral],  and the tear in your eye. Though not in math, but in other areas, I have had similar experiences, and can appreciate what a great feeling it is. And I have not found others speaking of similar situations, so I was very happy to see your expression...

For sure, if there is reincarnation, I hope to remember to ask my mother to get your books for me when I am about 6.

Anyhow, I am going to pretend I am 6 or so, and play around with your material. I have a 3 year old grandson and I have great hopes that I can get him off to a good start in understanding mathematics.

Thanks for the inspiration and good ideas.


Dean E.

21 October 2010   "why small animals are nocturnal (SA/Vol ratio)" See Nanako's work on this problem  and on the MAP.

 12 October 2010 See Lori Johnson Morse's 4 Wolfram Demonstration Projects, based on Don's book Changing Shapes With Matrices. Check out Lori's website at 

 9 October 2010 from an email to Don:

Hi Mr. Cohen, 
I am a past student of yours and I was just thinking about you the other day and thought I would see how you were doing. You taught me about 11 years ago until my family moved to Chicago. I have since graduated college with the idea that I would be premed, but found myself in a Master's of Science program in epidemiology and biostatistics. I haven't had a math course since freshman year of college but I am loving statistics and I am currently applying to PhD programs in biostatistics as well as medical school. 

I wouldn't have the math abilities that I do today if it weren't for some of the guidance you gave me early on. In fact, when I doubt my math background I always remember your encouragement. 

Before I moved you gave me a watercolor of a tornado. It was the first picture I hung up in my new room and I think of you every time I see it. I hope you and your family are doing well and you are still helping students learn to enjoy and appreciate mathematics.

Thank you for everything you did for me in the past.

--Maggie P.

9 October 2010 Our granddaughter Tara and fiancee Tyler, won "favorite commuter/travel biking blog"- at . You can see their bicycle route from Glasgow, Scotland, through Europe and north Africa, with a journal, pictures, and sound bytes along the way. Congratulations guys! We are proud of your fine work and hard bicycling around the world. They bought a car in Berlin then drove to Ulan Bator, Mongolia, with bicycles in the trunk. They took a plane to Bangkok, Thailand today and will go to LopBuri where Don's Thai son has a room for them at he and his sister's restaurant. After bicycling around Asia, they plan to leave for home from Kuala Lumpur, Maylasia.
29 September 2010 See Don's new page containing hands-on materials, lessons, puzzles and games he uses with his students
                    A test of Don's calculus program

The synopsis of a paper that was  presented at  the 23rd International Congress of Applied Psychology in Madrid, Spain, July 1994, by Janie Shaklee:


SHAKLEE, Janie; McGILL, Karen; PULOS, Steven; COONEY, John and Teresa McDEVITT, University of Northern Colorado, Greeley, Colorado, USA.

D. Cohen developed a cognitive instructional program for teaching calculus to children. This study was conducted to systematically implement and evaluate the program's effectiveness in lower-socio economic status classroom environment. Twenty-six ten year-old students received instruction in the calculus concepts of limits and infinite series using Cohen's approach. An adjacent classroom, which also had 26 students, served as a control. Pre tests and post tests in calculus concepts understanding and attitudes to mathematics were administered to both groups. Results indicated that ten year old students can learn calculus concepts in a group instructional format. While the pretest indicated a lag in scores achieved by girls, there were no significant gender differences in the post tests. We conclude that the teaching and learning of calculus can be achieved in mainstream classrooms using the conceptual instructional program designed by Cohen".

9 August 2010 Xander, 7 yo, came from SC to work with Don for a week, 9 August-13 August 2010. See his work here (not complete yet).

4 August 2010 The recording of Don's virtual "talk" is now up on the page at the Math 2.0 wiki: http://mathfuture.wikispaces. com/Calculus+by+and+for+Young+ People There were about 35 participants from around the world (New Zealand, UK.., one of Don's students Ashley, and her Mom, Lori Johnson Morse from KC, and a teacher who Don had as a student circa 1970 in NYC). Don introduced people to his clickable A Map to Calculus, showing Donna's graphing of x2 + y2 = 25, then changing something in the equation and seeing what happens..very exciting!
Best stats presentation you'll ever see, at rosling_shows_the_best_stats_ you_ve_ever_seen.html

On this day 6 June 2010, Don & Mrs. Cohen met Sheri, on the way out of a restaurant where she was working. It was great to see her. She will be a sophomore at the U of Michigan in the Fall, loving it, majoring in Neuroscience, and aims to be a doctor! Her sister Amanda whom Don also worked with, will be a senior at the U of CA, San Diego, and is planning to go to law school. 

Besides seeing his own children, grandchildren and greatgrandchildren grow up, it's also a pleasure seeing his students grow up. Especially when he has had their children; one former student helped Don set up his website and one, Jonathan, has helped make his A Map to Calculus clickable! Don feels very fortunate to have positively affected so many young people. Mrs. Cohen has been the greatest supporter of his work and the love of his life for the last 57 years.

2 June 2010 Congratulations Lori Johnson Morse!! Her new, fine, Wolfram Mathematica Demostrations Project submission: ChangeTheDogMatrixTransformations has been accepted for publication. It does the matrix transformations Don has in his book Changing Shapes With Matrices, in a new way!

21 May 2010 David, an 7th grader, is very good at figuring out hard functions (we've played a lot of Guess My Rule lately, instigated mainly by Jerry, Anna, and David). Don asked him how he did this. He announced to Don today that he had a way of doing it- his "Rule Generator" or how he can come up a function from about 7 pairs of numbers!  He is presently writing this up for the world.. Stay tuned.

19 May 2010  From the Mom of Don's student from NZ, many years ago, on facebook: "Hi Don, It was William you taught calculus to. How he loved your classes! He is now grown up (mostly) and doing very well working in IT. Best wishes"

17 May 2010  an email to Don: 

Dear Don,

I was a student of yours about ten years ago.  I just wanted to send you a
little note to let you know that I still very often use the most important
lesson that you taught me: when a problem is too difficult, first think of
an easier case of the problem and work from there.
I am now a student at the California Institute of Technology, studying
Chemistry.  I very much enjoyed working with you when I was younger, and I
don't recall whether I ever really got to thank you, so I wanted to make
sure that I did that.


Don was so pleased to hear from Geoffrey. See his work at Geoffrey, age 11, graphs the 6 trig functions ,  Geoffrey generalizes the infinite series, Geoffrey works on powers of powers, Geoffrey worked on the Fibonacci numbers. Search Geoffrey, above to see other fine things he did.

Time lapse here due to Don working on his MAP

1 January 2010 An email to Don from Japan

Dear Don and Marilyn,

Hello! How are you? I didn't have a chance to visit you

last summer, but I hope I can soon

I hope that both of you will have a

Happy New Year

These are some pictures of my dog Fluffy, and I!! Did you

 recognize that your painting was in one of the pictures




-Nanako came to work with Don for a week in the summers of 2007 and 2008! See her work at ,         

19 December 2009 From a holiday card: Dear Don, The boys (and I!) have learned a lot this year and are looking forward to more math in the New Year! We are blessed to have you in our lives. - Shawna N. [the Mom]

3 November 2009 Anna L., a 4th grader, does some fine mathematics
1 November 2009 Don has worked on math for 9 years with Jay, now a HS Jr. Don and his wife Marilyn were invited to Jay's Vedic ceremony BRAHMOPADESHEM, celebrating a period of education or preparation for life. In the photo below, his father, considered the ultimate guru, imparts the "secret" of the Gayathri Mantra to his son Jay, with the help of the Priest.

It was a beautiful ceremony.

25 October 2009 an email to Don, used with permission:

RE: Mathematics - See what an Educator and young students can produce!  FYI – I’m forwarding email sent to me by Don Cohen about his students’ recent work [ Van & Jack below]. Don wrote Calculus By and For Young People (ages 7, yes 7 and up) . I’ve known Don since the early 1990s, and I have used his materials in my classrooms.

·   If you are a young person, studying mathematics with Don Cohen is a great investment.

·   If you know a young person, point them to study mathematics with Don Cohen-- a great investment.

·   If you are an educator – Don Cohen is a great mentor and a really nice guy.

- from Dr. Debbie Denise Reese, the senior educational researcher at the NASA-sponsored Classroom of the Future (COTF) within Wheeling Jesuit University’s Center for Educational Technologies in Wheeling, WV

14 October 2009 Van, a 4th grader, graphs in 3D
6 October 2009 Jack invents new ways of looking at mathematics
5 October 2009 Do you understand? In 16 languages so far; do you know another?
27 September 2009 Zion made up the problem: 52.65 - 83.50 = - 31.15 Was he right?
20 September 2009 While iterating a function, Laura, a 4th grader, divides 7.75 by 2- WOW!
26 August 2009  And Anushka, age 6, knew neither division nor graphs !
20 August 2009 Don shows below that the limit of the infinite series 2/5 + (2/5)2 + (2/5)3 + (2/5)4
+ ... = the area within the orange triangle. Note that the terms of the series alternate being tall rectangles (the odd powers) and squares (the even powers). Don connected the orange diagonal line from the point (0,1) through the upper right corners of the squares. He found the slope of this line to be -3/4 and the y-intercept 1; then he found the x-intercept to be 4/3.

Notice that the piece above the diagonal orange line in the tall rectangles, equals the area below the orange line above the square to its right. Notice also that the length of the base of the orange triangle = 2/5 + 2/5 + (2/5)2 + (2/5)2 + (2/5)3 + (2/5)3 +(2/5)4 +(2/5)4  ... = 2* [2/5 + (2/5)2 + (2/5)3 + (2/5)4 ...]. The area within the orange triangle = (1/2)(base x height) = (1/2)(2x [2/5 + (2/5)2 + (2/5)3 + (2/5)4 ...])x1= 2/5 + (2/5)2 + (2/5)3 + (2/5)4 + ... , the sum of the infinite series whose limit is 2/3. This is also 1/2x4/3x1= 2/3 and also 2/(5-2) = 2/3. This last one comes from doing lots of series and students generalizing A/B + (A/B)2 + (A/B)3 + (A/B)4 ... -> A/(B-A).

Below you can see Lori Johnson Morse's applet  for this, made in GeoGebra.

13 August 2009 Don received this email:

"Love your book

Hi Don,

I ordered your book "Calculus By and For Young People" a few years ago, even before my children were ready for it (my oldest was just turning 5). It's a good thing I ordered it before they were ready because I wasn't ready for it yet. But my wife and I were homeschooling our children, and I was looking for new ideas for teaching mathematics, so I started reading them.

I'm not a math-phobic person. I'm currently completing my PhD in Computer Science. My wife isn't math-phobic either, and she earned a B.S. in Electrical Engineering.

Still, as I read your book, I felt like I was experiencing math in a whole new way. I felt like there was truths in the book that were mind-blowing. I read it several times before I started to understand that Calculus wasn't the main point of your book. Learning, Living and Loving mathematics were the core of your book and Calculus was just the vehicle.

This year, Alex is 7 and he's really advancing in his schooling. We were preparing (over the Summer) our curriculum for the fall and your book was going to be Alex's text. Then I was sent the Paul Lockhart article, "A Mathematician's Lament" by a friend. It had a powerful impact on me, but I couldn't have understood that article, without first reading your book. The two together helped me come up with a Math "method" that I am now using with Alex that is just amazing. He has a math notebook, similar to an engineer or scientist's notebook, that we use every day to explore math problems. We're currently exploring the math problems in your book "Calculus, by and for young people." As we learn new formulas, we add them to another section of his notebook we call the "Formula Toolkit". I do have Alex do some drill problems every day based on things that are in his "Formula Toolkit", but Alex knows that the drills aren't the math, they're simply the tools to help him do real math. Thanks to your book, and Lockhart's article, mathematics will never be the same again for me, or for my children.

Thank you again for your amazing contribution!

(PS, I have a home schooling blog at It's not all about math, but you might like to read my post about "The Joy of Mathematics").

-- Seth Nielson

[See for Lockhart's article "A Mathematician's Lament".]

[Don thinks Seth really understands what Don's book is about! -and a second linking of Paul Lockhart's article and  Don's works in 2 months. Check out his blog- a real math teacher in the making. Thank you Seth.]

11 August 2009  Guess who came to visit with Don and his wife? Yes Kirsten,

who was 8 yo in this picture, which is on the back cover of Don's Worksheet Book. Don worked with Kirsten from age 4 when she was at The Montessori School of C-U, through age 15 at UNI high (when she got a 5 on her AP Calculus test). She is now about 28 yo, having graduated form U of Munich (in German!) a couple of years ago, and is now teaching German and English in Beijing, China and engaged to be married next year.

15 July 2009 Shaleen moves a parabola 2 units to the right and something else happens!- or an example of what the teacher does to allow good mathematics to come from a situation, when the student's answer is different from what is expected or would be considered "wrong". 
7 July 2009 Don received an email out of the blue. "Freeman Hunter is now following your updates on Twitter". I looked at her Twitter site with the update 

Check out @TheMathman website, esp example probs. Could his method be one answer to The Mathematician's Lament (see Paul Lockhart's 25 page paper   on math education)

[WOW!! Thank you Freeman].

19 June 2009 Don received this email:

Dear Don,
I don´t know if you remember us, but we came to see you for a week about six years ago.  My son Johann was five years old.  I have thought of you so often and how you inspired our family. Johann loves math and now our younger son Tristann is also learning to love math through his interest with origami.  I don´t know why we didn´t keep in touch with you, but somehow life got in the way.

I would like to be able to bring my kids back, I know they would love it.  I am so impressed with how you teach and your love of math.  I would love to hear from you.

Svava (

7 June 2009 A conversation between Maya, 8 years old, Don, a TI-84 plus calculator, and WolframAlpha, to find the sum of 2+1/2+4+1/4

4 June 2009 Just so you know that Don is not perfect. From a note to Don from one of his mothers: Mr. Cohen, Could you work on some basics with Sarah. Addition, subtraction, multiplication, division, counting money, and word problems. She still got a C-  in Math.. Thanks, Frances C. [Sarah is continuing to work with Don through part of the summer].

2 June 2009 From a note to Don from one of his fathers: Don, The kids had a very good year with you. In addition to all the things they learned about geometry, numbers and puzzles, I think they've absorbed the most important idea: math is fun!

I hope you have a good summer, and I know the kids look forward to seeing you again in the fall.- Charles

22 May 2009 From a note to Don from one of his mothers: "Thanks for helping Jesse to his "A" in math! Fondly, K. [Jesse was taking algebra when he started with Don in Dec. '08 with an "E" (for failing- of course he didn't hand in homework), and by the end of January, a month later, he got an "A" and continued that until the end of the school year!]
7 May 2009
- a note from a parent of 3 of  Don’s students, along with a check for May:
Hi Don! I wanted to mention that we might send Jack to you this summer- and have Joe take the summer off. If Joe’s schedule allows him to go to you, we’ll send both boys.

You have made a huge difference in Joe’s life! Certainly his confidence and skills in math have increased- but your (and Marilyn’s) influence goes beyond that. You model for him an attitude and approach to life that he very much admires. I believe it really does “take a village” to raise a child. I feel mighty good that you both are part of Joe’s “village”- that you have been a part of all of our children’s village. Thank you! Bernadette

1 May 2009

from: Maria Droujkova<>

subject: Changing Shapes With Matrices - in the Math Clubs!  

This is an activity designed by Don Cohen-The Mathman, in his book "Changing Shapes with Matrices." You can find some sample book problems here, and follow links to other Don's materials:

The general idea is to start with a simple "dot to dot" picture on a coordinate plane, and then apply a matrix transformation to coordinates of every dot.
Like many activities involving massive number crunching, it works much better on computers. [That’s why Don starts with a simple “doggie” with only 9 integral points, and limits students to only 1’s, 0’s and
-1’s to form the transformation matrix, so there is not a lot of number crunching]. You can experiment with this applet, transforming a doggie, on Don's site [made by IES in Japan] at:

…Kids could quickly test conjectures, such as: "What makes the shape flip? How can you stretch the shape more? What happens if you put opposite numbers in the matrix? Reciprocal fractions? Zeroes?" This was some excellent math by kids - the reason I love this activity so much.

…We did some very meaningful math and had a lot of fun with the activity. Don, thank you very much for your wonderful books, full of great activity ideas. 

For Maria’s complete article, go to    

Thank you Maria, for sharing this activity with your google group.

28 April 2009 Don and his students Jay, Chris, and Elizabeth find a new number- the Dottie number
2 April 2009
Check out Don's granddaughter Tara and fiance Tyler on their world trip by bicycle at - they started April 1 in Scotland, rode through England, France, Switzerland, Italy are now in Tunisia at this time (28 November 2009)! See the article about them in the April 20 issue of The Champaign-Urbana News-Gazette.
30 March 2009 From a note to Don from one of his mothers: Dear Mr. Cohen, ..We are  fortunate that Mildred was able to work with you this past year.. We will always happily recommend your services to others and would not hesitate to contact you in the future if we should find Mildred in need of additional math tutoring. Thanks for everything. T.C.
23 March 2009 from an email

Dear Don,

 ..Ashley received her letter of acceptance into the Radiology Program at Parkland College on Saturday, March 21, 2009 and is so excited about that!  Thank you again for assisting her with her Math!  If she ever needs any future tutoring, we would certainly give you a call.

Julie (Mom)

20 March 2009 From Michael's Mom: Don, Thank you for working with Michael [8 months via email- see some of his work below]. Maybe we can come spend a few days in person with you this summer...

Michael is really enjoying your calculus worksheets. Thanks again!!  Sincerely, Theresa (WI)

26 February 2009 Dear Lori Johnson Morse, my friend and fellow math tutor wrote a little article about Don which was accepted on an eNY Times page- take a look.
18 February 2009 See Malcolm Gladwell's book Outliers The Story of Success. Chapter 8 is entitled: Rice Paddies and Math Tests. Lots of interesting connections and without knowing these, Don had his Calculus.. book translated into Japanese and
sold much better in 10 years in Japan than the original English version has sold in 20 years in the US.
2 February 2009   Email: “I heard about your product (2 disk CD set) from a homeschooling family that is registered with the same DL school [in Canada ] that my children are and they recommended it”.- Karen T., after she purchased same.
23 January 2009 Email from Don's Facebook file

Subject: Thank You! 

I just wanted to drop you a line and tell you how much my girls and I have enjoyed your math program. Last year we bought the Calculus program at our home school convention, and my girls have not put it down since. They are so excited about math and it has become their favorite subject. Thank you so much! Julie, GA

Thank you Julie, for sharing this wonderful information!

November, and 10 December 2008 Ann-Emily, 2nd grader, adds fractions using complex fractions and multiplies mixed numbers-WOW! (and Don never taught her how to do any of this)
As a teacher, Don likes this quote by an anonymous writer who said: "We have not succeeded in answering all your problems. The answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe we are confused on a higher level and about more important things".

Mathematics in Science: Michael has been working through Don's worksheet book and with Don via email, for about 8 months. In chapter 6 there is a diagram of hinged mirrors at left, below. Students are asked to look between the mirrors to see how many images of a red rod, say, that they see with the mirrors open at an angle of 90o (3 + the original=4). 

Michael made the diagram at the right below, using an angle of 60 between the mirrors, and proceeded to show the path of the light rays as they leave the red rod, bounce off the mirrors (the angle of incidence equals the angle of reflection) and to go to the eye, He found the 6 images (5+original=6); and they all lie on the same circle!

  And there is a rule here.                                                  

Fine job Michael!!

Fine applets to interact with -you need to download free Java program to view these:

     The Nautilus Shell applet done by Lori and Don - you need to download free, geogebra

    Area of triangle= limit of infinite series, applet done by Lori and Don - you need to download free, geogebra

     Changing Shapes With Matrices  applet done by IES in Japan to go with Don's book of this title

    The six trig functions in one picture applet done by IES in Japan- upon Don's recommendation

    The difference of 2 cubes (Maggie, 9 years old, builds a box..and does some algebra)- applet done by IES in Japan- upon Don's recommendation

    (a+bi)^(a+bi)^ ...  applet done by IES in Japan, inspired by Don's  problem of i^i^i... in his Worksheet Book, Chapter 11 -IES as usual, did a great job with this, ending up with fractals!

10 October 2008 Don received this note from the mother of her 11th grade student:

Dear Mr. Cohen

Thank you for being a teacher and an example to Elizabeth and other kids in math and in life. 


1 - 3 October 2008 Mathematics in Nature: Aaron, Don's grandson, brought him a sunflower head cut from his garden; it was about a foot in diameter. The seeds grow in spiral arrays in 2 directions. See the photo below that Don took of the sunflower head, then added the numbers. Maddie, a 5th grader, with Don, counted the rows of seeds in the one direction going clockwise around the sunflower head (starting and ending in the lower left of the picture). They colored the starting or first row red and every 10th row red, to help keep track of the counting. The rows bend sometimes, not perfect spirals, which makes it difficult to count. Then Don and some other students finished counting those and the rows in the second direction, again going clockwise around the sunflower head, coloring the starting or first row black and every 10th row black

There were 89 rows in the one direction and 55 rows in the other direction, both Fibonacci numbers, including 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ... see the pattern?

See the sample problems from chapter 7 in Don's worksheet book and you'll find that Don has his students use the infinite sequence of the Fibonacci numbers to get the ratios of these. They are working with infinite sequences, ratios, fractions, mixed numbers, division,  decimals, infinite repeating decimals and finding patterns. The infinite sequence of  ratios has a limit which turns out to be The Golden Mean or The Divine Proportion, 1.618033... which  equals (1+ Sqrt(5))/2. 

Don's son Brian made a beautiful, wooden 3-D diorama for the story written by Don's granddaughter Tara, for her UNI HS geometry class, at age 15, entitled  A Quest For The Sacred Golden Pineapple, Pine Cone and Artichoke.  The diorama includes 1.) a figurine of The Old Mathman holding a golden pineapple, made by Tara, within a dome, 2.) a watercolor painting by Tara and Don of The Old Mathman's house in the woods, and 3). a shelf underneath with a copy of Tara's story.

26 September 2008 Don received this email from the mother of a former student:

Hi Don,

For ages I have been thinking about getting in touch with you - and hope that this e-mail address still works. I'm not sure that you'll remember Andy from about 12-13 years ago, but if you do I thought I'd give you an update. He graduated from U of I with majors in math and physics in 2006 and then went on to grad school in physics at Harvard in the Fall of 2006. He finished his Masters in January 2008 and then decided that he really didn't want to be an experimental physicist. So, he's now on a 2-year leave from the program and working as an energy analyst for ___ in downtown Boston . He is very happy to be making $ and really engaged in his work. In fact, he seems all grown up and indeed an adult.

I hope that you are well and still the mathman. Andy really benefited from working with you, and I always enjoyed talking with you too. Have a good October.


It has been 20 years (1988) since Don published his book Calculus By and For Young People (ages 7, yes 7 and up) . It was reviewed in the Dec. 1988 issue of Scientific American magazine. It is still selling, now on CD Rom, and on his 2-disk CD set Calculus For Young People . Then came Calculus By and For Young People-Worksheets with questions leading to the different ideas. Then 2 videos (Infinite Series and Iteration),  A Map To Calculus and Changing Shapes With Matrices. All items are now on his 1 DVD set Calculus For Young People  

It has been 10 years (1998) since Kodansha Ltd. published the Japanese translation of the original book.

Mr. Sasaki at Kodansha Ltd., wrote to Don a month after they published the Japanese translation of Don's book Calculus By and For Young People (ages 7, yes 7 and up) in 1998: "We can say that your method was accepted to Japanese people as a kind of new text in which they could learn and understand math much more than ever before".

Needless to say, Don's Japanese book has sold much better in 10 years, than the original English version in the US in 20 years!

Back in 1988, Don felt his book was 20 years ahead of its time, and now in 2008 he still feels it is 20 years ahead of the math taught in schools- of course it's not just the book, but also his methods of teaching.

10 September 2008- 20 February 2009 Erin has made 16- 3x3x3 cubes with the 7 Soma pieces and drawn the layers to help others make a cube. Erin is amazing; she keeps coming up with new ones, and can tell if it is different from the others- of course she checks them!
22 August
2008 From Michael's Mom"Do you like to see the parents involved..?" Don's response: Yes, even to have you child explain something to you. I had Sheri as a 4-6th grader; now she is a 12th grader taking Calculus. I worked with her for about 3 hrs individually over the last month (August 2008). Today, a week into her calculus class, she told me 'What we did the last 3 weeks (derivatives), the teacher did with my class in one day, and I was like the only one in the class that understood what she was talking about! It really helped for me to talk with you about the problems as I worked on them'. On Don's main page, search "Sheri" to see what she did as a 4th-6th grader!
11 August 2008 Sara
& Maya, age 7 (twins), find Patterns in division

21 July 2008 Alex, a 2nd grader, sees an infinite series!!!
27 June 2008 Mom and Dad with their 6 children, drove down from North of Chicago. Mom and 4 children, 3 girls and 1 boy, worked with Don for 2 hours, while Dad and their two youngest children went off to the park. Click here to see what they worked on.
17 June 2008 Don received this thank you note from Paul, who came to Don from 3rd grade through 12th grade:
Dear Mr. Cohen,
Thank you very much for the beautiful graduation card, the gift card to Pages For all Ages, and for attending graduation. Even more significantly, thank you for providing a strong foundation in mathematics and for helping me through subjects I found especially difficult. Your innovative approaches and teaching styles kept math interesting and fun, while the teaching methods in school made it dull and repetitive. This approach has been something that I can apply to different aspects of my life, by looking at a topic from a different angle, I am able to much more thoroughly comprehend the subject.

Once again, thank you so much for all you've done.
Sincerely, Paul

Thank you Paul, for your dedication to excellence and being a wonderful human being, and to Mom and Dad, for making it all possible! You all have helped make the last 10 years of my teaching very enjoyable.

16-21 June 2008 Nanako came from Japan again to work with Don!
3 May 2008 Don & Marilyn were in Albany, NY to accept his 2008 Excellence in Education award- see the program and Don after his speech . Don wants to thank the Alumni Association of UAlbany, SUNY, his friends, students and parents of his students who wrote to support his nomination. Don realizes though, that this award is not as important as his work with individual students over the years-and for that he is most grateful. It has been a great ride!

While in Albany, he and Marilyn drove past Bethlehem Central Junior High School (now Middle School) where Don started his math-teaching career in 1954!

April 2008 Margaret, an 8th grader, asks a great question!
1-DVD,  "Calculus For Young People (1 DVD)", ISBN 9780977949311, contains all of Don’s materials -3 books, 2 videos, map, & poster, listed here: 

1. "Calculus By and For Young People (ages 7, yes 7 and up)”
2. "Calculus By and For Young People--Worksheets"
3. "A Map to Calculus"-- a 15" x 18"
, overview
4. Video #1 "Infinite Series By and For 6 year-olds and up"
5. Video #2 "Iteration to Infinite Sequences with 6 to 11 year-olds"
6. "Changing Shapes With Matrices"
7. “On thinking About and Doing Mathematics”-11x14” poster  

The 1DVD  above, for PC and Mac users, sells for $70.95

PayPal Checkout above. 

Note: Shipping on all items is FREE in the US, 

To outside U.S. email Don for S&H.


Besides the 1 DVD above,
Don will continue to sell these
, paid
via PayPal/check only:

"Calculus By and For Young People (ages 7, yes 7 and up)"    (CD-ROM);

ISBN 9780977949304 ______$23.95 (also on 1 DVD)

 "Calculus By and For Young People--Worksheets"
ISBN 9780962167478 ___________
$35.95 (also on 1 DVD )

"A Map to Calculus"-- a 15" x 18" poster-flowchart;
        ISBN 9780962167485___________ $
13.95 (also on 2 CD set)

"Changing Shapes With Matrices" (paper);
ISBN 9780962167430 __________$

15.95 (also on 2 CD set)

See what Rainbow Resource Center says about Don's materials.

1 January 2008 What a way to start the new year! Don spoke to Jonathan (now 26 years old) and his Mom and Dad who are in CT.  Jonathan, at age 7, started working in Don's book Calculus By and For Young People (ages 7, yes 7 and up), with his Mom acting as his secretary. She sent his work to Don. (This started Don on his Math By Mail/Email Program). That and the following summer, his Dad brought him to Champaign for a week to work with Don. Some of Jonathan's work is in Don's worksheet book and he is on his videotapes.

Jonathan has finished the course work for his PH.D. in High Energy Physics and is working on his dissertation, which he plans to finish next year!

Don is very pleased when his students do well!

What a wonderful year 2007 has been. If we could only have Peace, and no one should go hungry!

28 December 2012: Don and his wife Marilyn celebrated their 60th wedding anniversary!

 199 July 2007:
113 June 2007: Leah's Mom called to tell Don that Leah got into UNI High School and would continue to work with Don in August when she returns to Champaign- Congratulations Leah!!

3 March 2007: Geometric Sequences and the 88 Keys on a Piano by Don

17 February 2007 Five views of  Don's Math Room - where it all happens!   

9 February 2007 Don received an order for his 2-disc CD ROM set (now 1 DVD) from Moscow, Russia !!
Check out  Lori's website for her "MathHead Tutoring Inc."

“..You wrote an amazing bookk

(Don's worksheet book).  Every week what my kids learn puts smiles on their faces.  It makes me smile, too.  You make people smile because they can understand math better.  It’s a gift and you share it with as many people as you can!  And I am having a blast following in your footsteps.  Much, much thanks! Lori”. KC, MO

See the internet links to Don's website and references to his books from around the world!

Homeschooling math by Don Cohen

                   “ ..Two roads diverged in a wood, and I - -
            I took the one less traveled by,
            And that has made all the difference.”

From The Road Not Taken  by Robert Frost. Don feels that what he has done is not the usual, and something that has touched many people, young and old, around the world, very positively, and has been very rewarding-  and that has made all the difference in his life!

To get around on Don's site, choose from the menu below:


Don's Materials Will Teach You To:
-New discoveries &

Patterns in Mathematics

Try sample problems from Don's worksheet book, by chapter!

Don's Materials
(all published and copyrighted by
Don Cohen-The Mathman)

Get Ready for Calculus

  1. Book: "Calculus By and For Young People (ages 7, yes 7 and up)" (CD-ROM)
  2. Worksheet book: "Calculus By and For Young People - Worksheets" (CD-ROM) & Table of Contents of books 1 & 2
  3. Videotape #1: "Infinite Series"
  4. Videotape #2: "Iteration"
  5. "A Map to Calculus"
  6. "Changing Shapes with Matrices"
  7. All of Don's materials are on 1 DVD (see above)

 Science to math activities
The non-trivial use of Calculators and Computers in Don's materials
The important mathematics

The importance of guessing
Patterns in Mathematics

Learn to
Learn -

Tessa at 5 works with Grandpa ! "When Grandma talks, everyone listens!"
What parents, teachers, kids, Martin Gardner, Morris Klein, W.W. Sawyer, the MAA, the ASCD, Kodansha, Mary Pride in her 'Big Book of Home Learning', the July/Aug. 2000 issue of The Home Education Magazine, The Math Forum.. say about Don's materials
On Thinking About and Doing Mathematics
Who was that Mathman?
'The Math Program'- Don and Jerry's great way of teaching math & loving it! (and what parents and students say about The Math Program)
How other sites use Don's ideas & his website
Don's Favorite Places on the WWW
Puzzles, Games, & Hands-On Activities Don Uses With Students
After 45 years of teaching math & parenting..
Links to this website- how many now ?

Don's materials are for grades K-12, ages 6-8 with adult help, up through pre-calculus students, adults, teachers, teachers of teachers, and parents!

Send email to Don Cohen concerning his 'Math by Mail/Email' with IM and video, coming to Champaign to work with him , ways he could improve his web site, or other issues. count traffic people have come in, peeked, glanced, shook, were curious, skeptical, impressed, excited, thought about what their children are doing in school or as homeschooled, tried a problem, solved a problem, emailed Don, called Don, ordered his material, .. since June 6, 1996. Notice, this site slipped past 200,000 visitors in early  2004- in less than 8 years!
                 Thank you for stopping, do try some problems before you go!

Don's web site was designed and started by one of his former students, Jennifer, while at MIT, and continued & maintained by Don, with some help from his grandson, Lian.