1) 21 - (5-8)

2) 3.7 - (4 - 5.3)

3) 1/6 - (5/12-7/12)

4) - 13 - (20-32)

5) - 4.5 - (7 - 9.5)

6) - 5/8 - (5/8-1)

7) - 18 - (9-5)

8) - 0.25 - (3 - 2.25)

9) - 2/9 - (1 - 8.9)

1) 21 - (5-8) = 21 - (-3) = 21+3=24

2) 3.7 - (4 - 5.3) = 3,7 - (-1,3) = 3,7+1,3=5

3) 1/6 - (5/12-7/12) = 1/6 - (-2/12) = 1/6+1/6=2/6=1/3

4) - 13 - (20-32) = - 13 - (-12) = 12-13=-1

5) - 4.5 - (7 - 9.5) = - 4,5 - (-2,5) = 2,5-4,5=-2

6) - 5/8 - (5/8-1) = - 5/8 - (-3/8) = 3/8-5/8 = - 2/8=-1/4

7) - 18 - (9-5) = - 18-4=-22

8) - 0.25 - (3 - 2.25) = - 0,25-0,75=-1

9) - 2/9 - (1 - 8.9) = - 2/9-7,9 = - 20/90 - 711/90 = - 731/90 = - 8 целых 11/90