The number twenty comes after nineteen and before twenty-one. It's written as 20 in numerals and represents two groups of ten, or ten plus ten.

Twenty shows up in many familiar places. Most classrooms have around twenty students. A twenty-dollar bill is worth twenty one-dollar bills. When you count by tens (10, 20, 30...), twenty is your second stop. In the game of darts, hitting the bullseye scores you fifty points, but the highest number on the board is twenty.

Twenty is also significant in how we structure larger numbers. After you count from one to twenty, the pattern changes: instead of unique names like “thirteen” or “seventeen,” you start combining words in a predictable way (twenty-one, twenty-two, and so on). This pattern continues through twenty-nine, then shifts again at thirty.

The word appears in some common expressions too. When someone has 20/20 vision, they can see clearly at a distance that is considered normal. If you play twenty questions, you get exactly twenty yes-or-no questions to guess what someone is thinking of. And hindsight is twenty-twenty means it's easy to see what you should have done after something has already happened.