3 пример, ответ: 9/65
1) 6 7/12 - 3 17/36 = 6 21/36 - 3 17/36 = 3 4/36 = 3 1/9
2) 3 1/9 * 2.5 = 3 1/9 * 2 5/10 = 28/9 * 25/10 = 14/9 * 25/5 = 350/45 = 7 35/45 = 7 7/9
3) 4 1/3 : 0.65 = 4 1/3 : 65/100 = 13/3 * 100/65 = 100/15 = 6 10/15 = 6 2/3
4) 7 7/9 + 6 2/3 = 7 7/9 + 6 6/9 = 13 13/9 = 14 4/9
5) 2 : 14 4/9 = 2/1 : 14 4/9 = 2/1 * 9/130 = 9/65