Uppercase, Lowercase

We have uppercase (capital) and lowercase (small) letters, but numbers are just numbers, aren't they? It turns out there are a couple of special cases where there are uppercase and lowercase numbers.

It exists in Chinese: 壹贰叁肆伍陆柒捌玖拾 for one to ten. It's supposed to prevent tampering of numbers and is still used in important documents (especially if money is involved)
The "lower case" is 一二三四五六七八九十, which can be altered easily - Reddit

The other case is typography, where they are sometimes called Oldstyle figures.

 Origin of the term here.