I'm trying to explain how Dungeon World works to someone who isn't familiar with the concept of having ability scores and modifiers based on them. So in DW, when you have a Constitution (CON) score of, say, 13, you have a CON modifier of +1. These modifiers are used all over, especially when rolling for a move.

What exactly are ability scores used for?

So far, I've been able to come up with the following list of things:

• Character creation: you choose scores from a list, or you roll 3d6.
• Hit points: your HP are your class base HP + your CON score.
• When you level up, you add 1 to an ability score.

Is that it?