
The above 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 shell ,
making
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's keys:
visualization,
look for patterns,
learn to learn
ようこそ; WELCOME
! عَلَى
الرُّحْبِ
والسَّعَة ;
환영받는;
¡bienvenido a casa!;
迎; 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.
Over
the past month
(May 2009),
at least 1
person came from every state in the US
to Don's website; the most came from
Illinois with 131.
About 1400 people
from 56 countries around the world,
came to Don's website, as shown in Google
Analytics.
Don
Cohen-The Mathman site search by
Google;
try
"Patterns in graphs", or "iteration", or
"Alex", ..
Excellent math instruction for K-12, and all
abilities - for 33
years!
prepare for UNI (SSAT), SAT+1&2, ACT, AP Calc, GED,
GRE
TESTS.
Adults, parents, and teachers,
are also welcome to come to learn mathematics. Call
today,
Don Cohen 217.356.4761
email
Don today at doncohenmathman@gmail.com
Don's address:
809 Stratford Dr. Champaign, IL 61821-
4140
Don is now accepting a limited number of students from afar, to come to
Champaign to work with him on
his Calculus For Young People program.
Don is also accepting a limited number of students
to work in his
Exciting
news- all the time!
Order Don's 2 CD set with
all
his
materials, @$70.95,
via Google Checkout or PayPal Checkout below or
check or money order.
Note: Shipping is
FREE in the US (IL add 7 3/4% tax).
To ship outside U.S. email Don for S&H
Google Checkout
Make Summer a big help for your children-
prepare for Fall classes; move ahead; understand math much better; learn
not to fear math; build confidence; get an early start on fractions, algebra,
geometry, trig, and calculus (ages 7 and up!);
Nanako, at ages 8 and 9, came from Japan
for a week each of the last 2 summers. Don uses a sunflower stalk for Nanako to obtain the
Fibonacci numbers. Finding their ratios, she got an infinite sequence
which approaches the Golden Mean (see ch.7 in Don's worksheet book).
Calculus By and For Young People-Worksheets book with him, via email.
PayPal Checkout
![]() |
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.
Warmly,
Svava (CA)
I hope you have a good summer, and I know the kids look forward to seeing you again in the fall.- Charles
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
from: Maria Droujkova<droujkova@gmail.com>
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:
http://www.mathman.biz/html/probcswm.html
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: http://www.mathman.biz/html/dogtrans6/changing_shapes_with_matrices%20ies6.html
…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
http://groups.google.com/group/naturalmath
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 friend Tyler. on their world trip by bicycle at
www.goingslowly.com
- they started in Scotland and are in
Dear Don,
..Ashley
received her letter of acceptance into the Radiology Program at
Sincerely,
Julie (Mom)
Michael is really enjoying your calculus worksheets. Thanks again!! Sincerely, Theresa (WI)
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!
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".
Michael made the diagram at the right below, using an angle of 60o 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!!
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
applet done by IES in Japan to go with Don's book of this titleThe 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!
Dear
Mr. Cohen Thank you for
being a teacher and an example to Elizabeth and other kids in math and in
life. Pat
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
10
October 2008 Don received this note
from the mother of her 11th grade student:
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.
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.
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
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.
Chris
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 2-disk CD 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.
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!
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"
flowchart
The
2-disk CD ROM set above, for PC and Mac users, sells for $70.95 on Google Checkout above.Note: Shipping on all items is FREE in the US,
To outside U.S. email Don for S&H.
------------
Besides the
two-disk CD set above,
Don will continue to sell these
"Calculus By and For Young People (ages 7, yes 7 and up)" (CD-ROM);
ISBN 9780977949304 ______$23.95 (also on 2 CD set)
"Calculus By and For Young People--Worksheets"
(CD-ROM);
ISBN 9780962167478
___________$35.95
(also
on 2 CD set)
"A Map to Calculus"-- a 15" x 18" poster-flowchart;
ISBN 9780962167485___________ $13.95
(also
on 2 CD set)
See what Rainbow
Resource Center says about Don's materials.
Jonathan has finished the
course work for his
"Changing
Shapes With Matrices" (paper);
ISBN
9780962167430
____SALE______$6.95
(also
on 2 CD set)
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.
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!
2 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!
7
February 2007
Don spoke to Loralee
Johnson at "4 Your Mind" and told people during the interview that Loralee is selling Don's materials in Edmonton,
Alberta, Canada and can be reached at 1-780-485-0969 or ljohnson@shaw.c
“..You wrote an amazing book
Marilyn and
Don Cohen are excited about their part-time work as Shaklee Distributors and
users of many Shaklee
“in harmony with nature”
products-100% guaranteed -nutritional supplements including the new VITALIZER, Get Clean, Cinch
inch-loss program, air purifier and more!- and they want to share these with
you. Please take a look at their Shaklee
website if you want to feel better, want a healthy home, a healthy planet, and
bring in some extra money.
19
July
2007:
Don
received this email from a parent who had purchased his 2-disc CD set:
"..I just wanted to say thank you again for inspiring me and helping me
realize that kids can understand and do so much more with math than many
people are willing to believe..".
13
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!!
9 February 2007
Don received an order for his 2-disc CD ROM set from
Moscow, Russia !!
Check
out
Lori's website for her "MathHead Tutoring Inc."
See the internet links to Don's website and references to his books
from around the world!Homeschooling math by Don Cohen
About Don's materials (7 items) and how they are used
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.