в)7 1/6 + 5 2/9 = 43/6 + 47/9 = (43 × 3 + 47 × 2)/18 = 129/18 + 94/18 = 223/18 = 12 7/18
г)4 + 1 7/9 + 2 5/12 + 5 2/9 + 7/12 + 3 1/4 = 4 + 16/9 + 29/12 + 47/9 + 7/12 + 13/4 =(4 × 36 + 16 × 4 + 29 × 3 + 47 × 4 + 7 × 3 + 13 × 9)/36 = 144/36 + 64/36 + 87/36 + 188/36 + 21/36 + 117/36 = 621/36 = 69/4 = 17 1/4
ё)6 3/4 + 7 5/12 + 3 1/4 = 27/4 + 89/12 + 13/4 =(27 × 3 + 89 × 1 + 13 × 3)/12 = 81/12 + 89/12 + 39/12 = 209/12 = 17 5/12