What is Base-20?

Base-20 is a number system that uses 20 different symbols instead of just 10 like we usually do.

Imagine you have a bag with 20 types of marbles, some are red, blue, green, and so on. Each color represents a number from 0 to 19. When you count, instead of counting up to 10 and then starting over with a new group (like we do in base-10), you go all the way to 20 before you start a new group.

Some people used base-20 long ago, especially those who counted on their fingers and toes! If you think about it, your hands have 5 fingers each, and your feet have 5 toes each, that’s 10 fingers and 10 toes, or 20 in total. So if someone was counting using both their hands and feet, they might naturally use base-20.

Let's say you're counting beans, and every time you get to 20, you put them into a new jar. In base-10, you'd put them in a new jar when you hit 10. With base-20, your number "20" would look like 10, the 1 means one full jar, and the 0 means no extra beans outside of it.

It’s just another way to count, kind of like how some people use base-12 when counting eggs in dozens!