15/7-(18/7+9/14)=(15/7-18/7)-9/14=-6/14-9/14=-15/14
6/7+ (4/5-3/10)=6/7+5/10=19/14
7/10-1/4+3/10-3/4=10/10-4/4=0
5/12+6/7+7/12=12/12+6/7=1又6/7
13/12-5/6+11/24=37/24-20/24=17/24
7/8-1/6-5/12=7/8-1/2=3/8
15/7-(18/7+9/14)=(15/7-18/7)-9/14=-6/14-9/14=-15/14
6/7+ (4/5-3/10)=6/7+5/10=19/14
7/10-1/4+3/10-3/4=10/10-4/4=0
5/12+6/7+7/12=12/12+6/7=1又6/7
13/12-5/6+11/24=37/24-20/24=17/24
7/8-1/6-5/12=7/8-1/2=3/8