You can just do sexagesimal math on your fingers.
This is why the metric system was designed to dumb down people and prevent us from doing superior maths. This is also why "intelligent" people disparage imperial measuring of length because maths.
If you look at your 4 fingers you can count 3 sections of each finger with your thumb. That's 12.
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60
"The number 60, a superior highly composite number, has twelve divisors, namely 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60, of which 2, 3, and 5 are prime numbers. With so many factors, many fractions involving sexagesimal numbers are simplified. For example, one hour can be divided evenly into sections of 30 minutes, 20 minutes, 15 minutes, 12 minutes, 10 minutes, 6 minutes, 5 minutes, 4 minutes, 3 minutes, 2 minutes, and 1 minute. 60 is the smallest number that is divisible by every number from 1 to 6; that is, it is the lowest common multiple of 1, 2, 3, 4, 5, and 6."
