The lessons on conversions can be great fun, even if it’s not until centuries later that you finally grasp why your teacher made you learn them.
You know, from Celsius to Fahrenheit, from anything metric to anything not.
It’s the message behind conversions that can be tricky: you have a perfectly sensible way to count things, right? It always works. And then your teacher casually tells you that other people have different perfectly sensible ways to count the exact same thing.
Well now what’s the all important advantage to that??
The neighborly thing to do is learn each other’s ways of counting. This minimizes confusion, and it’s faster than twiddling your thumbs and wondering why the world leaders don’t just play a quick round of rock scissors paper to settle once and for all on the International Way To Count.