In how many ways can you roll either a sum of 4 or a sum of 11 with a pair of dice?

(i don't understand the mathematical way)

For 4:
You can do-
- 1 and 3
- 2 and 2

For 11 you can do-
- 1 and 10
- 2 and 9
- 3 and 8
- 4 and 7
- 5 and 6

So you can roll 2 different ways to get a sum of 4, and 5 different ways to get a sum of 11

What numbers add to 4?
2,2
2,2 (other side)
1,3
3,1

what numbers add to 11?
5,6
6,5

4+2=6
6 ways I would say