5/6-2/3+1/8
=20/24-16/24+3/24
=4/24+3/24
=7/24
7/10+3/8-1/5
=28/40+15/40-8/40
=43/40-8/40
=35/40
=7/8
5/16+(1/9+8/9)
=5/16+1
=1又5/66/11+7/8-6/119/23+(14/23-9/20)9-8/17-9/1713/32-(3/4-3/8)3/13+6/7+10/132-8/13-5/136/11+7/8-6/11=6/11-6/11+7/8=0+7/8=7/89/23+(14/23-9/20)=9/23+14/23-9/20=1-9/20=11/209-8/17-9/17=9-(8/17+9/17)=9-1=813/32-(3/4-3/8)=13/32-3/8=13/32-12/32=1/323/13+6/7+10/13=3/13+10/13+6/7=1+6/7=1又6/72-8/13-5/13=2-(8/13+5/13)=2-1=1