3/4 : 2/3, 1/3 : (3/4+2/3), (1/3+1/2):(3/7-2/5) 8 12/15+ 5 8/10, 4/15+4/8+4/7+31/56, 1/9+3/16+3/9-2/9 3/8 :7/16, 4/31:7/8
3/4+2/3=1 5/12
3/5-1/3=4/15
3/4-2/3=1/12
3/4+2/14=1/2
1/4-1/6=1/12
3/5+1/3=14/15
4/5+3/4=1 11/20
7/10-1/4= 9/20