> Egypt was the first ones to really start doing this: they had a duodecimal system already, so that's why it was split as base twelve, or our two parts of twel

> Egypt was the first ones to really start doing this: they had a duodecimal system already, so that's why it was split as base twelve, or our two parts of twelve hours in a day. If you're like me and immediately said ohhhhhhhhhhhh, so THAT'S why there's twelve hours in a day! The reason why we use numbers like 12 and 60 and 360 in time and length, from ancient times onwards to today, is because these numbers have many divisors, meaning that they can be divided many different ways without needing decimals. 12 can be divided by 1, 2, 3, 4, 6, 12 (i.e., it can be divided in half, into thirds, fourths, sixths). By comparison, you can't cleanly divide 10 into thirds or fourths without using decimals. 60 can be divided a whole bunch of ways: it can be divided by 1,2,3,4,5,6,10,12,15,20,30,60. The same is true for 360 (e.g. degrees in a circle). Even in the modern era, where we understand decimals and everyone is trained on them, it's convenient to be able to perform common operations on common units without having to involve decimals. It's convenient that an hour can be divided into three 20-minute periods, or two 30-minute periods, or six 10-minute periods, and so on.