а) 7 2/13 2 = 7 13/13 + 2/13 * 2 = 91/13 + 4/13 = 95/13

б) 5 7/16 8 = 5 16/16 + 7/16 * 8 = 80/16 + 56/16 = 136/16 = 17/2 = 8 1/2

в) 8 3/28 5 = 8 28/28 + 3/28 * 5 = 224/28 + 15/28 = 239/28