Respuesta :

8 1/3

   13
-  21 = 8

  2/3
- 1/3 = 1/3

8 1/3
fancygirl1
so first you can do it 21-13 then you get 8 after you subtract 2/3 - 1/3 and you get one third you don't have some the fraction into a common denominator because it is already the same. so therefore the answer is 8 1/3