(x, why?) Comics – All about math!

(x, why?) Comics is a geeky and hilarious comic about math. It is created by Chris Burke, a high school math teacher in New York as well as a part-time writer, and a fan of science-fiction / fantasy books and films.
He started making his own math webcomic totally by accident as a way of
amusing his students and trying to make them think just a little bit

You can check out over 300 geeky comics at: xwhy.comicgenesis.com

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Funny Math Fail Pics

100% Discount Store
discount store sign fail

25 years of partners in education
25 years of partners in education

Verizon Communications – What now, bitches?
cheque to verizon communications silly math

This restroom is closed from…

the restroom is closed from sign fail

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Top ln(e^10) reasons why e is better than pi

10) e is easier to spell than pi.
9) Pie without e just doesn’t taste that good.
8) The character for e can be found on a keyboard, but pi sure can’t.
7) Everybody fights for their piece of the pie.
6) ln(pi) is a really nasty number, but ln(e) = 1.
5) e is used in calculus while pi is used in baby geometry.
4) ‘e’ is the most commonly picked vowel in Wheel of Fortune.
3) e stands for Euler’s Number, pi doesn’t stand for squat.
2) You don’t need to know Greek to be able to use e.
1) You can’t confuse e with a food product.

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Using Fibonacci for mile <--> km conversion

The Fibonacci sequence:
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, …
can be used to convert miles to kilometers (and vice versa). For example, to find how many km 5 miles is, take the next Fibonacci number which happens to be 8. Thus, 5 miles is approximately 8 km. Similarly, 8 miles is approximately 13 km, and so on.

This works because the growth rate of the Fibonacci numbers converges to the golden ratio (approx 1.618) which happens to be very close the km/mile conversion (1 mile = 1.609 km).

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How to Make a Yoshimoto Cube

The following is a tutorial about how to make the Yoshimoto cube using paper (though it takes a very long time!). To make it you’ll need paper, scisors, some glue and some adhesive tape.

How to Make a Yoshimoto Cube origami

You can check out a non-paper version here.

To make one yourself you can print out the following Yoshimoto sheet and try to assemble it yourself 🙂

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Statistician jokes

A statistician is someone who loves to work with numbers but doesn’t have the personality to be an accountant.

Q: How do you save a drowning statistician?
A: Take your foot off his head.

Two statisticians were travelling in an airplane from LA to New York. About an
hour into the flight, the pilot announced that they had
lost an engine, but don’t worry, there are three left.
However, instead of 5 hours it would take 7 hours to get
to New York. A little later, he announced that a second
engine failed, and they still had two left, but it would
take 10 hours to get to New York. Somewhat later, the
pilot again came on the intercom and announced that a
third engine had died…
Never fear, he announced, because
the plane could fly on a single engine. However, it would
now take 18 hours to get to New York. At this point, one
statistician turned to the other and said, “Gee, I hope we don’t lose that last engine, or we’ll be up here forever!”

In earlier times, they had no statistics, and so they had to fall back on lies.

Are statisticians normal?

Statistics are like a bikini – what they reveal is suggestive, but what they conceal is vital.

Statistics in the hands of an engineer are like a lamppost to a drunk–they’re used more for support than illumination.

The average statistician is just plain mean.

The average Australian has one testical and one breast and less that two legs!

Statisticians do it……

Statisticians do it continuously but discretely.

Statisticians do it when it counts.

Statisticians do it with 95% confidence.

Statisticians do it with large numbers.

Statisticians do it with only a 5% chance of being rejected.

Statisticians do it with two-tail T tests.

Statisticians do it. After all, it’s only normal.

Statisticians probably do it.

Statisticians do it with significance.

Probabilists do it on random walks.

Probabilists do it stochastically.

Statisticians do all the standard deviations.

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Math Grape Jokes

Q: What’s purple and commutes?
An Abelian grape.

Q: What is purple and all of its offspring have been committed to institutions?
A simple grape, it has no normal subgrapes.

Q: What is lavender and commutes?
An Abelian semigrape.

Q: What’s purple, commutes, and is worshipped by a limited number of people?
A finitely-venerated Abelian grape.

Q: What’s purple, round, and doesn’t get much for Christmas?
A finitely presented grape.

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Funny Math Jokes

Q: What is green and homeomorphic to the open unit interval?
The real lime.

Q: What is yellow, linear, normed and complete?
A Bananach space.

Q: What do you call a young eigensheep?
A lamb, duh!

Math and Alcohol don’t mix, so… Please Don’t Drink and Derive!

Q: What is a proof?
One-half percent of alcohol.

Q: What’s the contour integral around Western Europe?
Zero, because all the Poles are in Eastern Europe!
Actually, there ARE some Poles in Western Europe, but they are removable!

Q:What is a dilemma?
A lemma that proves two results.

Q: What’s a polar bear?
A rectangular bear after a coordinate transform.

Q: What’s nonorientable and lives in the sea?
Moebius Dick.

Q: What does the little mermaid wear?
An Algebra.

In Alaska, where it gets very cold, pi is only 3.0. As you know, everything shrinks in the cold. They call it Eskimo pi.

Q: Why didn’t Newton discover group theory?
Because he wasn’t Abel.

Q: What do you get if you divide the cirucmference of a jack-o-lantern by its diameter?
Pumpkin Pi!

Alex: What’s your favorite thing about mathematics?
Jake: Knot theory.
Alex: Yeah, me neither.

Life is complex. It has real and imaginary components.

Q: Why did the mathematician name his dog Cauchy?
Because he left a residue at every pole.

Q: What do you get if you cross oatmeal with a duck?

Q: What is a topologist?
Someone who cannot distinguish between a donut and a coffee cup.

Q: What is a compact city?
It’s a city that can be guarded by finitely many nearsighted policemen.

Q: Why can’t you grow wheat in Z/6Z?
It’s not a field.

Q: What’s grey, huge and has integer coefficients?
An elephantine equation.

Q: What is used by Canadians (and people from Wisconsin) to help solve certain differential equations?
The Lacross transform.

Q: What is clear and used by trendy sophisticated engineers to solve other differential equations?
The Perrier transform.

Q: What is very old, used by farmers, and obeys the fundamental theorem of arthimetic?
An antique tractorization domain.

Q: Why couldn’t the moebius strip enroll at the school?
They required an orientation.

Q: Why did the chicken cross the Moebius strip?
To get to the other…

Q: What did Zero say to Eight?
Nice belt.

Q: Did you hear the one about the statistician?

Q: Why do mathematicians, after a dinner at the Mandarin, insist on taking the leftovers home?
Because they know the Chinese remainder theorem!

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Speed Math via Vedic Mathematics

Vedic mathematics is based on sixteen su-tras which serve as somewhat cryptic instructions for dealing with different mathematical problems. Below is a list of the su-tras, translated from Sanskrit into English. They were presented by a Hindu scholar and mathematician, Jagadguru Swami Sri Bharati Krishna Tirthaji Maharaja, during the early part of the 20th century.

  1. By one more than the previous one
  2. All from 9 and the last from 10
  3. Vertically and crosswise (multiplications)
  4. Transpose and apply
  5. Transpose and adjust (the coefficient)
  6. If the Samuccaya is the same (on both sides of the equation, then) that Samuccaya is (equal to) zero
  7. By the Para-vartya rule 
  8. If one is in ratio, the other one is zero.
  9. By addition and by subtraction.
  10. By the completion or non-completion (of the square, the cube, the fourth power, etc.)
  11. Differential calculus
  12. By the deficiency
  13. Specific and general
  14. The remainders by the last digit
  15. The ultimate (binomial) and twice the penultimate (binomial) (equals zero)
  16. Only the last terms
  17. By one less than the one before
  18. The product of the sum
  19. All the multipliers

The first one is basically the multiplication algorithm by 11 discovered independently by Trachtenberg.

Let us look at the second one, which is used quite a bit in Vedic Mathematics: All from nine and the last from ten.

subtracting from a large power of ten with many columns of zeros, it is
not necessary to write the notation for borrowing from the column on
the left. One can instead subtract the last (rightmost) digit from 10
and each other digit from 9. For example:


method is also used when finding the deficit from the next larger power
of ten when setting up a multiplication problem using the
cross-subtraction method.

The third one is Vertically and crosswise (multiplications). One use for this is for multiplying numbers close to 100.

you want to multiply 88 by 98. Both 88 and 98 are close to 100. Note
that 88 is 12 below 100 and 98 is 2 below 100. This can be pictured as


subtract crosswise to get the first two digits of the answer. It
doesn’t matter if we do 88-2=86 or 98-12=86, both give the same number.
To get the last two digits we multiply vertically: 12 x 2=24.
Therefore, the answer is 8624.

The same strategy works for
multiplying two numbers above 100. For example, 107 times 111. Quickly
we add the surplus from 107 (which is 7) to 111 to get 118, the first 3
digits of the answer. To get the last two digits, we multiply the
surplus of 107 from 100 by the surplus of 111 from 100: namely, 7 x
11=77. Thus, the answer is 11,877.

Vedic Mathematics is all about using different formulas in a variety of ways.
In the above rule we are using:
The above notation is short for:
and is often used since it’s easier to see what the number actually is.

above generalizes for numbers close to a base of 1000. Note that the
second su-tra becomes quite useful for when you are computing the
deficit from the base.

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The Trachtenberg Speed System

Who was Trachtenberg?

  • Professor Jakow Trachtenberg was the founder of the Mathematical Institute in Zurich, Switzerland.
  • He was a Russian, born June 17th, 1888 and studied engineering.
  • While still in his early twenties, he became Chief Engineer with 11,000 men under his supervision.
  • After the Czar of Russia was overthrown, he escaped to Germany where he became very critical of Hitler. He was later imprisoned.
  • Most fellow prisoners around him gave up hope and died even before being sent to their death. He realized that if he wanted to stay alive, he had to occupy his mind with something else rather than focus on the hopeless conditions surrounding them. He set his mind on developing methods to perform speed mathematics.
  • With the help of his wife, he escaped from prison and fled to Switzerland.
  • There, he taught his speed math system to young children. It was very successful.

Trachtenberg developed a set of rules (algorithms) to multiply long numbers by numbers from 0 to 12. These rules allow one to dispense with memorizing multiplication tables, if that is desired.
Even better, it gives a way to help memorize them, by allowing one to
work out the answer by rule if one cannot remember it by rote. We
perform each rule starting at the far right. The `number’ is the digit
of the multiplicand just above the place that we are currently
computing. The `neighbour’ is the digit immediately to the right of the
`number’. When there is no neighbour, we assume it is zero. We also
write a zero in front of the multiplicand.

Note that the following rules only use the operations of addition, subtraction, doubling, and `halving’.


Download the file trach.pdf for some examples. Also see the book: Trachtenberg, Jakow (1960). The Trachtenberg Speed System of Basic Mathematics. Doubleday and Company, Inc.
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