1) 5/6 - 2/3 = 5/6 - (2 * 2)/(3 * 2) = 5/6 - 4/6 = 1/6. Проверка: 5/6 - 1/6 = 4/6 = 2/3. Ответ: 1/6; 2) 17/18 - 5/6 = 17/18 - (5 * 3)/(6 * 3) = 17/18 - 15/18 = 2/18 = 1/9. Проверка: 17/18 - 1/9 = 17/18 - 2/18 = 15/18 = 5/6. Ответ: 1/9; 3) 5/8 - 5/24 = (5 * 3)/(8 * 3) - 5/24 = 15/24 - 5/24 = 10/24 = 5/12. Проверка: 5/12 + 5/24 = (5 * 2)/(12 * 2) + 5/24 = 10/24 + 5/24 = 15/24 = 5/8. Ответ: 5/12; 4) 1/2 - 3/10 = (1 * 5)/(2 * 5) - 3/10 = 5/10 -3/10 = 2/10 = 1/5. Проверка: 1/5 + 3/10 = 2/10 + 3/10 = 5/10 = 1/2. Ответ: 1/5.