Отыскать значение разности а 1-8/15б 3-2/11в 4-3 4/9

Первый пример.

1 - 8/15 = 1/1 - 8/15 = 1 * 15/1 * 15 - 8 * 1/15 * 1 = 15 15 - 8/15 = 15 - 8/15 = 7/15;

2-ой пример.

3 - 2/11 = 3/1 - 2/11 = 3 * 11/1 * 11 - 2 * 1/11 * 1 = 33/11 - 2/11 = 33 - 2/11 = 31/11 = 9 + 2 * 11/11 = 2 9/11;

3-ий пример.

4 - 3 4/9 = 4/1 - 3 4/9 = 4/1 - 3 9 * + 4/9 = 4/1 - 31/9 = 4 * 9/1 * 9 - 31 * 1/9 * 1 = 36/9 - 31/9 = 31 - 31/9 = 5/9.