## I put my thing down, flip it and reverse it

Since we all know that the day after Thanksgiving is Math Friday, and we all need to know matrix multiplication for our everyday lives, it's perfect that we now have this lovely tool.
posted by selfnoise on Nov 25, 2016 - 12 comments

## Animated math

Essence of linear algebra - "[Grant Sanderson of 3Blue1Brown (now at Khan Academy) animates] the geometric intuitions underlying linear algebra, making the many matrix and vector operations feel less arbitrary."
posted by kliuless on Sep 11, 2016 - 17 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

## Is there any point to the 12 times table?

Is there any point to the 12 times table?
posted by Cat Pie Hurts on Jun 27, 2013 - 159 comments

For twenty years, the fastest known algorithm to multiply two n-by-n matrices, due to Coppersmith and Winograd, took a leisurely O(n^2.376) steps. Last year, though, buried deep in his PhD thesis, Andy Stothers discussed an improvement to O(n^2.374) steps. And today, Virginia Vassilevska Williams of Berkeley and Stanford, released a breakthrough paper [pdf] that improves the matrix-multiplication time to a lightning-fast O(n^2.373) steps. [via]
posted by albrecht on Nov 29, 2011 - 50 comments

## Who's afraid of the seven times table?

Who's Afraid of the Seven Times Table? Ernst Kummer, one of the great mathematicians of the late 1800s, was hopeless at arithmetic. He was giving an advanced maths lecture and in the middle of a complicated calculation he needed to know what six times seven was. “Um ... six times seven is ... six times seven . . .” A student put up his hand: “41, Professor.” Kummer chalked 41 on the blackboard. “No, no, Professor!” shouted another. “It’s 44!” Kummer gave the students a quizzical look. “Come, come, gentlemen. It can’t be both. It must be either one or the other!”
posted by storybored on Sep 27, 2011 - 168 comments

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