Per mil

Per mil is a way to talk about a fraction that is really tiny. Imagine you have a pizza that is cut into 1000 teeny-tiny pieces. That's like a tiny, tiny piece of pizza, right? Well, if you wanted to talk about just one of those teeny-tiny pieces, you could say "one per mil."

Now, why would anyone want to talk about pizza that is cut into such tiny pieces? Well, it turns out that per mil is a way we talk about things in different fields. For instance, in finance, people might talk about interest rates as "two per mil." That would mean that for every thousand dollars you borrow, you have to pay back an extra two dollars.

So, per mil is just a way to talk about a really tiny fraction, like one little piece of a pizza that is cut into a thousand pieces. It's often used in fields like finance to talk about interest rates or other financial information.