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 .
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.
Don's keys:
visualization,
look for patterns,
learn to learn
New: Don Cohen-The Mathman site search by Google; try "Patterns in graphs", or "iteration", or "Alex", ..
Excellent math instruction for all ages, and all
abilities - for 32
years!
Start any time.
Don Cohen 217.356.4761 Jerry Glynn 217.328.1640
Email Don
Exciting news- all the time!
Order Don's 2 CD set with all his materials, @$70.95,
via Google Checkout below.
Note: Shipping is FREE in the US.
To outside U.S. email Don for S&H
Dear DAD,
Greetings from the
Your postcard can be found here:
http://parklink.disney.go.com/parklink/dis/pi/missionspace/2008-11-28/
http://www.apple.com/quicktime/
"Dat's my boy dat did dat!"- after comedian Jimmy Durante- we've got to have a sense of humor!
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!
Fine job Michael!!
not ready yet The Nautilus Shell done by Lori and Don
Changing Shapes With Matrices done by IES in Japan for Don's book
More coming!
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 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. 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 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. Don Cohen and Lori Johnson Morse,
August 14, 2008, Created with GeoGebra
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)”
The
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. 
26 September 2008
Don received this email from the mother of
a former student:
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
10 September 2008 Erin
has made 14- 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!
11 August 2008 Sara,
age 7, finds Patterns in division
14 August 2008 Look
at and try the applet that Don and Lori created while she was here and finished
at this date, using
GeoGebra.
This applet shows Don's discovery that the sum, or limit, of an infinite series
equals the area of a triangle.
You can choose the numerator(a) and the denominator(b) of the fraction A/B.
Notice that the base
of the triangle is twice
the infinite sum.
Area of triangle = sum of infinite series
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!
April 2008 Margaret,
an 8th grader, asks a great question!
Don's 2-disk CD
set,
"Calculus For Young People
(2 CD set)",
ISBN 9780977949311,
contains
all
of Don’s materials -3 books, 2 videos, map, & poster, listed here:
2. "Calculus By and For Young People--Worksheets"
3. "A Map to Calculus"-- a 15" x 18"
flowchart
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
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,
"Calculus By and For Young People (ages 7, yes 7 and up)"
(CD-ROM);
Don will continue to sell these
"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
See the
internet links to Don's website and references to his books
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."
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.
Don's Materials
Will Teach You
To:
