1) 1/2+4/7-3/4 = 14/28+16/28-21/28= 9/28
2) 1/7+2/3-1/2 = 6/42+28/42-21/42 = 13/42
3) 2/9+3/4-3/5 = 40/180+135/180-108/180 = 67/180
4)1/2+1/4+1/8 = 4/8+2/8+1/8 = 7/8
5)7/30-2/15+1/6 = 7/30-4/30+5/30 = 8/30
6)5/12+5/6-3/4 = 5/12+10/12-9/12 = 6/12 = 1/2
7)4/9-3/10+1/2 = 40/90-27/90+45/90 = 38/90 = 19/45
8)5/8+1/10-7/25 = 125/200+20/200-56/200 = 89/200