math
posted by hind .
7. ____ is two thirds of ____
8. ____ is three quarters of ____
9. ____ is a quarter of ____
10. ____ is a third of ____

I would start with the of part first...
for example if you are dealing with thirds, choose numbers like 3, 6, 9 something that is divisible by 3.
For quarters use 4, 8, 16
I will get you started with # 7
I will start with 9
_____ is 2/3 of 9 Multiply 2/3 time 9 which = 18/3 or 6.
6 is 2/3 of 9. 
2 , 3
3 , 4
1 , 4
1 , 3
plus an infinite number of bigger answers