## Can you add faster than a 5 year old

CMA is a "brain development program designed to develop higher learning capability and aims to promote mental arithmetic, enhance memory, boost creativity, and increase focus using the principle of Abacus". Watch some kids from The Philippines calculates in seconds, using their fingers. (SLYT)
posted by growabrain on Aug 20, 2015 - 14 comments

## "Their little heads are exploding"

Mrs. Nguyen’s Prestidigitation From a set of 1 through 9 playing cards, I draw five cards and get cards showing 8, 4, 2, 7, and 5. I ask my 6th graders to make a 3-digit number and a 2-digit number that would yield the greatest product... and somehow we end up with lacing diagrams and Python. (The original post on Fawn Nguyen's blog)
posted by Wolfdog on Jun 22, 2015 - 18 comments

## 3Blue1Brown: Reminding the world that math makes sense

Understanding e to the pi i - "An intuitive explanation as to why e to the pi i equals -1 without a hint of calculus. This is not your usual Taylor series nonsense." (via via; reddit; previously)
posted by kliuless on Jun 6, 2015 - 28 comments

## Arithmeticfilter

Nothing but an endless supply of mental arithmetic problems. Five levels of difficulty, from "10 - 6" to "√370881."
posted by Iridic on Jan 26, 2015 - 20 comments

## The one that is the smaller is the larger

The Teaching of Arithmetic: The Story of an experiment. In the fall of 1929 I made up my mind to try the experiment of abandoning all formal instruction in arithmetic below the seventh grade and concentrating on teaching the children to read, to reason, and to recite - my new Three R's. And by reciting I did not mean giving back, verbatim, the words of the teacher or of the textbook. I meant speaking the English language. I picked out five rooms - three third grades, one combining the third and fourth grades, and one fifth grade. I asked the teachers if they would be willing to try the experiment.
posted by Wolfdog on Mar 8, 2014 - 18 comments

## How can nothing can be something?

While the concept of shunya or "zero", both as place holder in the decimal system and as "null" or "nothingness" has been historically attributed to the Indian mathematician/astronomer Aryabhata, it was when I went to search for its history and impact that whole new world was revealed. From culture and art to spiritual practice, the concept of zero has captured the imagination of many throughout the ages. Books have been written, its origins debated while the etymology of the word itself sometimes replaces understanding. From a disconcerting concept of nothingness to the ubiquitous misspelling of the one followed by a hundred zeros, Shunya today is more than just the gaping void it originally represented.
posted by infini on Feb 7, 2014 - 55 comments

## A Compassionate "Human Computer", RIP

Shakuntala Devi, the Indian "human computer," passed away on Sunday. The NY Times first did a profile on her when she visited the US in 1976, during which she computed the cube root of a 9 digit integer in her head, but could not remember that she had been to the US once before -- over 20 years prior. Bob Bemer (inventor of the Escape key previously) remembers meeting her in 1953 on the TV show You Asked For It (which had previously featured a race between an abacus and a calculator). Psychologist Arthur Jensen (who did controversial research on race and IQ) wrote a paper on Shakuntala's exceptional ability in 1990. Shakuntala made her living as an astrologer and authored numerous books mostly on mathematical puzzles and tricks, but also The World of Homosexuals (1977), one of the earliest ethnographic studies of gay people in India. Specifically about gays in her hometown of Bangalore, Shakuntala called for "not only the decriminalisation of homosexuality in India, but also its 'full and complete acceptance' by the heterosexual population so that the Indian homosexual may lead a dignified and secure life."
posted by bluefly on Apr 23, 2013 - 28 comments

## Computerized Math, Formal Proofs and Alternative Logic

Using computer systems for doing mathematical proofs - "With the proliferation of computer-assisted proofs that are all but impossible to check by hand, Hales thinks computers must become the judge."
posted by kliuless on Mar 16, 2013 - 25 comments

## The ternary calculating machine of Thomas Fowler

The ternary calculating machine of Thomas Fowler. And electromechanical calculating machines from the 1960s.
posted by Wolfdog on May 28, 2012 - 11 comments

## Machines of Paper and Wood

Building a Computer 1: Numerals - recently my kids have been asking me about how computers work. I like to give in-depth answers to such questions, so we set out on a quest to understand how they work... Follow-up parts 2 3 4 5 6 7 8 9 10 11 12 13 14 15.
posted by Wolfdog on Oct 20, 2011 - 17 comments

## There's definitely a method to my madness. Definitely.

Lightning calculator and "mathemagician" Art Benjamin goes through his paces in a 15 minute video.
posted by Wolfdog on Dec 19, 2007 - 32 comments

## Let's Party Like It's MCMXCIX

Roman Numerals and Arithmetic
posted by jack_mo on Aug 19, 2006 - 19 comments

## Incan Binary!

The Incas had binary! Archaeologists have long known that khipu strings were used by the incas to store arithmetic records. Now, it's believed that they used a 7-bit binary code to store all kinds of "written" information. Well? Who's going to be the first to translate Harry Potter onto a khipu string?
posted by unreason on Jun 23, 2003 - 8 comments

## Tests show U.S. children lag behind

Tests show U.S. children lag behind A careful reading of this page reveals that for many of America's schools, children lag behind some 16 other countries in math and in science. However: not all states contributred data. But the important thing is that a few schools and areas were right up there with the best in the world. Perhaps then we ought to study those that work instead of bashing our educational system in general.