Explain how you can use a number line to find the sum

Let's say you wanted to add 2 and 7

One way is you start at 2 on the number line, then move 7 units to the right until you land on 9. This visually shows 2+7 = 9.

Or you could start at 7 and move 2 units to the right, and you'll end up at 9 as well. You can think of it like 2+7 and 7+2 are the same thing.