(1)1-1/6+1/42+1/56+1/72+1/90(2)5/4-9/20+11/30-13/42+15/56-17/72+19/90(3)1/3+3/4+2/5+5/7+7/8+9/20+10/21+11/24+12/35

1－1/6 +1/42 +1/56 +1/72 1-1/6＋1/42+1/56+1/72 1-6分之1+42分之1+56分之1 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72 1/2+1/6+1/12+1/20+1/30+1/42+1/56 简算 1/2+1/6+1/12+1/20+1/30+1/42+1/56简算, 简便运算：1/2+1/6+1/12+1/20+1/30+1/42+1/56 2/1+6/1+12/1+20/1+30/1+42/1+56/1=? 1/6+1/12+1/20+1/30+1/42+1/56+1/72 简便计算 1-1/6+1/42+1/56+1/72+1/90+1/110怎么简便 1/2 - 1/6 - 1/12 - 1/20 - 1/30 - 1/42 - 1/56怎么算 1/2+1/6+1/12+1/20+1/30+1/42+1/56 1/2-1/6-1/12-1/20-1/30-1/42-1/56等于多少 2/1+6/1+12/1+20/1+30/1+42/1+56/1= 1/2+1/6+1/12+1/20+1/30+1/42+1/56= 1/2+1/6+1/12+1/20+1/30+1/42+1/56 1/2+1/6+1/12+1/20+1/30+1/42+1/56