(1) 7/18 : 28/15 = 7/18 * 15/28 = (сокращаем) 1/6 * 5/4 = 5/24
Ответ : 3
(2) ( 5/6 : 3/13 ) × 6/5
1) 5/6 : 3/13 = 5/6 * 13/3 = 65/18
2) 65/18 * 6/5 = 13/3
Ответ : 1
(3) 7/12 * 6/17 + 1/8 : 17/6
1) 7/12 * 6/17 = 7/2 * 1/17 = 7/34
2) 1/8 : 17/6 = 1/8 * 6/17 = 1/4 * 3/17 = 3/68
3) 7/34 + 3/68 = 14/68 + 3/68 = 17/68 = 1/4
Ответ : 2
(4) 21/13 : х = 7/26
х = 21/13 : 7/26
х = 21/13 * 26/7
х = 3 * 2
х = 6
Ответ : 3
(5) 1) 7 : 9 = 0.8
2) 6 : 5 = 1.2
3) 8 : 11 = 0.7
4) 8 : 9 = 0.9
Наименьшее 0.7
Ответ: 3