Closed graph

A closed graph is like keeping all your toys safe in a toy box with a lid. It means that if you have two sets of things, one on the bottom and one on the top, they won't mix together. Just like the toy box keeps your toys separated and safe, a closed graph keeps two different sets of points separate from each other. This is important in math because we use graphs to show relationships between numbers, and we want to make sure they don't get mixed up. So, a closed graph is a way to make sure everything stays in its proper place and doesn't get messy or confusing.