# Math

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## It's My Birthday Too, Yeah

Me, Myself and Math , a six-part series by Steven Strogatz, looks at us through the lens of math. By an amazing coincidence my sister, Cathy, and my Aunt Vere have the same birthday: April 4. Actually, it’s not so amazing. In any extended family with enough siblings, aunts, uncles and cousins, you’d expect at least one such birthday coincidence. Certainly, if there are 366 people in the family — more relatives than days of the year — they can’t all have different birthdays, so a match is guaranteed in a family this big. (Or if you’re worried about leap year, make it 367.)
Me, Myself and Math , a six-part series by Steven Strogatz, looks at us through the lens of math. No other number attracts such a fevered following as the golden ratio. Approximately equal to 1.618 and denoted by the Greek letter phi, it’s been canonized as the “Divine Proportion.” Its devotees will tell you it’s ubiquitous in nature, art and architecture. And there are plastic surgeons and financial mavens who will tell you it’s the secret to pretty faces and handsome returns. Not bad for the second-most famous irrational number.

## Proportion Control

by Maria Popova What Medieval mathematics have to do with remix culture, publishing entrepreneurship, and gamification. Imagine a day without numbers — how would you know when to wake up, how to call your mother, how the stock market is doing, or even how old you are? We live our lives by numbers.

## Kevin Slavin: How algorithms shape our world

Flow chart of an algorithm ( Euclid's algorithm ) for calculating the greatest common divisor (g.c.d.) of two numbers a and b in locations named A and B. The algorithm proceeds by successive subtractions in two loops: IF the test B ≥ A yields "yes" (or true) (more accurately the number b in location B is greater than or equal to the number a in location A) THEN, the algorithm specifies B ← B − A (meaning the number b − a replaces the old b ). Similarly, IF A > B, THEN A ← A − B. The process terminates when (the contents of) B is 0, yielding the g.c.d. in A. (Algorithm derived from Scott 2009:13; symbols and drawing style from Tausworthe 1977).

## Algorithm

From placeholder to the driver of calculus, zero has crossed the greatest minds and most diverse borders since it was born many centuries ago. Today, zero is perhaps the most pervasive global symbol known. In the story of zero, something can be made out of nothing. Zero, zip, zilch - how often has a question been answered by one of these words?

## Binary

Binary numbers --- Introduction --- Addition --- Multiplication --- Counter --- Card game Since we learn about numbers when we're young, it's easy to think that this is the only way to count and do arithmetic. But it isn't. We count in Arabic numbers , which are base 10 or decimal, probably because we have ten fingers. You count from 1 to 10 using your fingers, and then use someone else's fingers to keep count of how many tens you have counted so far.