1)4 2/7-1 4/9=. 8 5/36-1 43/108=

Первый пример.

4 2/7 - 1 4/9 = 2 53/63;

4 2/7 - 1 4/9 = 4 * 7 + 2/7 - 1 * 9 + 4/9 = 30/7 - 13/9 = 30 * 9/7 * 9 - 13 * 7/9 * 7 = 270/63 - 91/63 = 270 - 91/63 = 179/63 = 53 + 2 * 63/63 = 2 53/63;  

Второй пример.

8 5/36 - 1 43/108 = 6 20/27;

8 5/36 - 1 43/108 = 8 * 36 + 5/36 - 1 * 108 + 43/108 = 293/36 - 151/108 = 293 * 108/36 * 108 - 151 * 36/108 * 36 = 31 644/3888 - 5436/3888 = 31 644- 5436/3888 = 26 208/3888 = 182 * 144/27 * 144 = 182/27 = 20 + 6 * 27/27 = 6 20/27.