Fast this is for my sister and i don't understand (30 points)

I don’t get most of it, but I believe “doubles” means two of the same number added together. For example, 9+9 is a double. I think “doubles +1” means a double and add one. For example, 6+6+1. If I were your sister, I would write “9+9 = 18” for doubles and “6+6+1 = 13” for doubles +1.

I hope I helped!

C. 1 1/2

Step-by-step explanation:

Hope this helps