Пошаговое объяснение:

21-(5-8)=21-(-3)=24

3, 7-(4-5, 3)=3, 7-(-1, 7)=5, 4

1/6-(5/12-7/12)=2/12 (-2/12)=0

-13-(20-32)=-13-(-12)=-1

-4, 5-(7-9, 5)=-4, 5-(-2, 5)=-2

-5/8-(5/8-1)=-5/8-(5/8-8/8)=-5/8-(-3/8)=-2/8=-1/4

-18-(9-5)=-18-4=-22

-0,25 -(3-2, 25)=-0, 25-(0, 75)=-1

-2/9-(1-8/9)=-2/9-(9/9-8/9)=-2/9-(1/9)=-3/9=-1/3