56. Преобразуйте десятичные дроби в обыкновенные и вычислите:

1) 0.5 - 2/7 = 1/2 - 2/7 = 7/14 - 4/14 = 3/14.
2) 0.53 + 5/16 = 53/100 + 5/16 = 212/400 + 125/400 = 337/400.
3) 8 11/24 - 5.35 = 8 11/24 - 5 35/100 = 8 11/24 - 5 7/20 = 192/24 + 11/24 - 100/20 + 7/20 = 203/24 - 107/20 = 1015/120 - 642/120 = 373/120.
4) 6.625 - 3 6/17 = 6 625/1000 - 3 6/17 = 6 5/8 - 3 6/17 = 48/8 + 5/8 - 51/17 + 6/17 = 53/8 - 57/17 = 901/136 - 456/136 = 445/136.