eli5: Every base is base 10

Question

Something I found while reading about base systems, I can’t really wrap my head around it. Maybe it has to do with fractions?

In: 41

Answer 1

It’s a joke, because every number written in its own base comes out as “10”, one-zero. It’s just not always ten.

What’s 2 in base two? 10

What’s 3 in base three? 10

What’s 16 in hex? 10

So if you ask what the base is of the number system you’re using, and they answer in that number system, the base is always “10”