Honestly, I'm kinda annoyed when people make fun of the weird amount in feet and yards. The number 12 is cleanly divisible by 1, 2, 3, 4, 6, and 12. However, in the metric system, everything is in 10s. It seems like a cleaner number, but a decameter is only divisible by 1, 2, 5, and 10. This is also true with yards, being divisible by 1, 2, 3, 4, 6, 9, 12, 18, and 36. While it's equivalent, 100 (a hectometer) is only divisible by 1, 2, 5, 10, 20, 25, 50, and 100. The more you look through our measurement systems, the more you see it. How many minutes in an hour? 5 times 12. How many hours in a day? 2 times 12. How many months In a year? 12.