The name was coined by a nine-year-old, Milton Sirotta, in 1920. Google’s name is a play on it.
Wacky Facts
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A “baker’s dozen” is 13.
Medieval bakers added an extra loaf to avoid being fined for short weight.
Pingala described binary numbers over 2,000 years ago.
The Indian scholar Pingala used patterns of short and long syllables that correspond to binary numbers in his work on poetic metre.
Aryabhata estimated pi to four decimal places.
In 499 CE he gave a value equivalent to 3.1416.
Every odd number in English has an “e” in it.
One, three, five, seven, nine — and all larger odd numbers end with one of those words.
Leap years skip three times every 400 years.
Years divisible by 100 are not leap years unless divisible by 400 — so 2000 was, 1900 was not.
Brahmagupta gave rules for negative numbers.
In 628 CE he described arithmetic with zero and negative numbers, calling them fortunes and debts.
111,111,111 × 111,111,111 = 12,345,678,987,654,321.
Squaring repunits (numbers made of 1s) produces palindromes up to nine digits.
Zero is an even number.
Zero divided by 2 is 0, a whole number, so it meets the definition of even.
1557The equals sign was invented in 1557.
Welsh mathematician Robert Recorde chose two parallel lines because “no two things can be more equal”.
“Forty” is the only number spelt with letters in alphabetical order.
F-O-R-T-Y: each letter comes later in the alphabet than the one before.
The number 6174 is magical.
Take a four-digit number with at least two different digits, sort digits high-low and low-high, subtract, and repeat. You always reach 6174 — Kaprekar’s constant, found by Indian mathematician D. R. Kaprekar.
Fold paper 42 times and it would reach the Moon — in theory.
Each fold doubles thickness: 0.1 mm × 2⁴² is about 440,000 km. In practice you cannot fold paper more than about 7–12 times.
A circle has the most area for its perimeter.
Of all shapes with the same boundary length, a circle encloses the largest area — which is why soap bubbles are round.
A shuffled deck of cards is almost certainly in a new order.
There are 52! — about 8×10⁶⁷ — possible orders, so a well-shuffled deck has likely never been in that order before.
In a room of 23 people, there is a 50% chance two share a birthday.
It feels wrong because we think of our own birthday, but there are 253 possible pairs among 23 people.
Ramanujan’s taxicab number is 1729.
It is the smallest number expressible as the sum of two cubes in two different ways: 1³ + 12³ and 9³ + 10³.
Pi has been calculated to trillions of digits.
Computers have calculated pi to more than 100 trillion digits; NASA needs only about 15 for spacecraft navigation.