А)5/8+1/4+7/12=15+6+14/24=35/24=1 11/25
б)5/6-3/8+1/12=20+9+2/24=31/24=1 7/24
в)3/7+11/14-2/21=18+33-4/42=47/42=1 5/42
г)1/5+1/7-1/9=63+45-35/315=73/315
д)13/18-1/24-(29/72+5/36)=13/18-1/24-(29+10/72)=13/18-1/24-39/72=13/18-1/24-13/24=52+3-39/72=16/72=2/9
е)(7/8-4/5)+(1/20+1/4)+1/2=(35+32/40)+(1+5/20)=67/40+6/20=67+12/40=79/40=1 39/40