Вычислите:
1. 2/17+7/17 7/16-5/16 2/25+9/25 12/13-3/13
2. 1-2/5 1-3/4 1-4/7 1-10/11

№ 1.

2/17 + 7/17 = 9/17

7/16 - 5/16 = 2/16 = 1/8 - сократили на 2

2/25 + 9/25 = 11/25

12/13 - 3/13 = 9/13

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№ 2.

1 - 2/5 = 5/5 - 2/5 = 3/5

1 - 3/4 = 4/4 - 3/4 = 1/4

1 - 4/7 = 7/7 - 4/7 = 3/7

1 - 10/11 = 11/11 - 10/11 = 1/11