№2 (4). Выполните действия.

а) 8/17 + 7/17 = 15/17, б) 28/43 - 15/43 = 13/43, в) 72/104 - 55/104 + 61/104 = 78/104 = 39/52, г) (61/82 - 12/82) + (32/82 - 25/82) = 49/82 + 7/82 = 56/82 = 28/41