system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why the brain works on even numbers or 5's.

When ever some body explains something they explain it in multiples of even numbers or 5's, why? 

I understand it is easier for working out for people just baffles me.
gpt
It's nothing to do with our brain - it's our number system.  Since our whole counting and math system is based on 10's, the cleanest ways to divide numbers up are in 2's and 5's.  So whenever we round or estimate, those are the numbers we gravitate towards - it's easy to recognize that 50 is half of a hundred, but harder to recognize how much 43 is.

If our number system were, say, based on 12's, then we'd naturally be thinking more in terms of 2's and 3's, as those are the most common factors of 12 (along with 4 and 6).  But with the sequence of 10's - 10, 100, 1000, etc., by far the easiest factors are 2 and 5.