выполните действия: 1)1/2 + 4/7 - 3/4; 5)7/30 - 2/15 + 1/6; 2)1/7 + 2/3 - 1/2; 6)5/12 + 5/6 - 3/4; 3)2/9 + 3/4 - 3/5; 7)4/9 - 3/10 + 1/2; 4)1/2 + 1/4 + 1/8; 8)5/8 + 1/10 - 7/25;

1/2 + 4/7 - 3/4 = 14/28 + 16/28 - 21/28 = 9/28

1/7 + 2/3 - 1/2 = 6/42 + 28/42 - 21/42 = 13/42

2/9 + 3/4 -3/5 = (8/36 + 27/36) - 3/5 = 35/36-3/5 = 175/180 - 108/180 = 67/180

1/2 +1/4 + 1/8 = 12/24 +6/24 +3/24 = 21/24 = 7/8

7/30 - 2/15 + 1/6 =7/30 - 4/30 + 5/30 = 8/30 =4/15

5/12 + 5/6 - 3/4 = 5/12 + 10/12 - 9/12 = 6/12 = 1/2

4/9 - 3/10 +1/2 = 40/90 - 27/90 + 45/90 = 58/90 = 29/45

5/8 + 1/10 - 7/25 = 125/200 + 20/200 - 56/200 = 89/200