Why is it that we count in tens, and measure in 12s.

i.e. dozen eggs, 360 degrees in a circle, 12 inches in a foot?

NC <><

The way of counting that has caught on, base 10 or decimal, has to do with the 10 digits (originally "fingers") on your hands. Other systems also make sense.

Base 12 or duodecimal is more easily divisible. But to actually CALCULATE in Base 12 you have to memorize bigger multiplication tables in order to multiply and use 2 more digits to include single digits for ten and eleven.

Base 10: 1, 2, 5, 10
memorize as high as 9x9

Base 12: 1, 2, 3, 4, 6, 12
memorize as high as 11x11

That's why we use 60 minutes and seconds. 60 is highly divisible because it's the least common multiple of 10 and 12, divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60.


Base 16 or hexadecimal is used by computers (along with base 2 or binary's "off" or "on" circuitry). Base 16 uses 0-9, and a-f for the digits ten through fifteen.

If the U.S. switches to the metric system, we would measure in 10s and in a systematic way. But you lose the greater divisibility of 12s.

[This message was edited by referenth on 07-08-02 at 03:53 PM.]

The ancient Babylonians used a system of base 60, which still survives in our smaller divisions both of time and of angle, i.e., minutes and seconds. In general, any integer n greater than one can be used as the base of a numeration system, and the system will employ n different digits.