1) 3 1/2+1 5/6; 2) 4 2/5+9 3/7; 3) 8 3/4+2 7/8; 4) 2 3/8+1 5/6; 5) 6 1/5+1 2/3; 6) 4 3/8+8 1/2. 15

1)3 1/2  +  1 5/6 = 7/2  +  11/6 =  (7 × 3  +  11 × 1)/6 = 21/6  +  11/6 =  32/6 = 16/3 = 5 1/3
2)4 2/5  +  9 3/7 = 22/5  +  66/7 =(22 × 7  +  66 × 5)/35 = 154/35  +  330/35 =  484/35 = 13 29/35
3)8 3/4  +  2 7/8 = 35/4  +  23/8 = (35 × 2  +  23 × 1)/8 = 70/8  +  23/8 =  93/8 = 11 5/8
4)2 3/8  +  1 5/6 = 19/8  +  11/6 =    (19 × 3  +  11 × 4)/24 = 57/24  +  44/24 =  101/24 = 4 5/24
5)6 1/5  +  1 2/3 = 31/5  +  5/3 =(31 × 3  +  5 × 5)/15 = 93/15  +  25/15 =  118/15 = 7 13/15
6)4 3/8  +  8 1/2 = 35/8  +  17/2 =  (35 × 1  +  17 × 4)/8 = 35/8  +  68/8 =  103/8 = 12 7/8