Пошаговое объяснение:

№1

1) 1 2/3 + 1 1/2 = 1 4/6 + 1 3/6 = 2 7/6 = 3 1/6

2) 1,5 * 3 1/6 = 15/10 * 19/6 = 5/10 * 19/2 = 1/2 * 19/2 = 19/4 = 4 3/4

3) 2 3/4 - 1,25 = 2 3/4 - 1 1/4 = 1 2/4 = 1 1/2

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

5) 1 1/2 * 5/6 = 3/2 * 5/6 = 15/12 = 5/4 = 1 1/4

6) 4 3/4 + 1 1/4 = 5 4/4 = 6

№2

1) 2 3/4 + 1 1/3 = 2 9/12 + 1 4/12 = 3 13/12 = 4 1/12

2) 1,8 * 4 1/12 = 18/10 * 49/12 = 3/10 * 49/2 = 147/20 = 7 7/20

3) 2 3/4 - 0,95 = 2,75 - 0,95 = 1,8

4) 3 1/4 - 2 1/3 = 3 3/12 - 2 4/12 = 2 15/12 - 2 4/12 = 11/12

5) 1,8 * 11/12 = 18/10 * 11/12 = 3/10 * 11/2 = 33/20 = 1 13/20

6) 7 7/20 + 1 13/20 = 8 20/20 = 9

№3

1) 2,8 : 1 2/5 = 28/10 : 7/5 = 28/10 * 5/7 = 4/2 * 1/1 = 4/2 = 2

2) 3 1/5 * 1 7/8 = 16/5 * 15/8 = 2/1 * 3/1 = 6/1 = 6

3) 2 + 6 = 8

4) 8 * 10 = 80