3/5 + 3/7 + 9/7 * 4/15
(7/9 - 1/6) : 2/9 * 21/22
7/8 + 5/8 * 1/3 + 2/3
(1/6 + 3/14) : (5/21 - 1/14)

3/5+3/7+12/35=21/35+15/35+21/35=48/35=1 13/35(14/18-3/18):2/9*21/22=11/18*9/2*21/22=11/4*21/22=21/8=2 5/87/8+5/24+2/3=21/24+5/24+16/24=42/24=7/4=1 3/4(7/42 + 9/42):(10/42 -3/42)=16/42:7/42=16/42*42/7=16/7=2 2/7