Look at these equations.
9 = 7 + a
a + 8 = b + 5
Use both equations to work out the value of b.

Beginner

11 = 5 + a

11 - 5 = a

6 = a

6 + 4 = b + 3

10 = b + 3

10 - 3 = b

7 = b

this may not be at all, but i use the same website you're using for school, and if i'm stuck doing one of these i try to look for it on the section.