Найти сумму:
3 5/9+7/12; 4/5+5 1/7; 18 2/5+8 2/3; 5 1/14+2 4/21

32/9 + 7/12 = (128 + 21) / 36 = 149/36 = 4  5/36

4/5 + 36/7 = (28 + 180) / 35 = 208/35 = 5  23/35

92/5 + 26/3 = (276 + 130) / 15 = 406/15 = 27  1/15

71/14 + 46/21 = (213 + 92) / 42 = 305 / 42 = 7  11/42