2/7+1/6 = 7/15-1/15 = 2/9+7/18 = 14/21-4/7 = 4/15+1/3 = 2/3-1/9 = 4/5+6/25 = 11/12-1/12 = 1/2+2/7 = 13/15-2/3 = 3/8+1/3 = 4/5-1/10 = 1/9+2/9 = 5/24-1/6 = 12/19+7/19

Для того, чтобы выполнить действия с дробями, нужно дроби привести к общему знаменателю. Далее по возможности сократить.

№1

2/7 + 1/6 = 12/42 + 7/42 = 19/42.

№2

7/15 - 1/15 = 6/15.

№3

2/9 + 7/18 = 4/18 + 7/18 = 11/18.

№4

14/21 - 4/7 = 14/21 - 12/21 = 2/21.

№5

4/15 + 1/3 = 4/15 + 5/15 = 9/15.

№6

2/3 - 1/9 = 6/9 - 1/9 = 5/9.

№7

4/5 + 6/25 = 20/25 + 6/25 = 26/25 = 1 1/25.

№8

11/12 - 1/12 = 10/12 = 5/6.

№9

1/2 + 2/7 = 7/14 + 4/14 = 11/14.

№10

13/15 - 2/3 = 13/15 - 10/15 = 3/15 = 1/5.

№11

3/8 + 1/3 = 9/24 + 8/24 = 17/24.

№12

4/5 - 1/10 = 8/10 - 1/10 = 7/10.

№13

1/9 + 2/9 = 3/9 = 1/3.

№14

5/24 - 1/6 = 5/24 - 4/24 = 9/24 = 3/8.

№15

12/19 + 7/19 = 19/19 = 1.