5 interesting math facts from Futility Closet

Math is not only mildly interesting, it is extremely interesting! Check out these awesome math facts from Futility Closet.

The sum of the numbers on a roulette wheel is 666.

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Take any number and rearrange its digits to form another number.
Subtract one from the other. The difference will always be divisible by 9.

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When asked his age, mathematician Augustus De Morgan used to offer a clue: “I was x years of age in the year x^2.” (He was 43 in 1849.)
That quirk puts De Morgan in a pretty exclusive club. Other members include Charles Atlas (who was 44 in 1936) and Jake Gyllenhaal (who will be 45 in 2025). Next up: Babies born in 2070 will be 46 in 2116.

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10! (that is, 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1) equals 3,628,800.
That’s also precisely the number of seconds in 6 weeks.

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Pick a three-digit number (example: 412).
Double it to create a six-digit number (412412).
Divide the result successively by 7, by 11, and by 13. There will be no remainders.
The result is the original number.

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