1/30+1/42+1/56+1/72+1/90 怎么用简便方法计算

1/30+1/42+1/56+1/72+1/90 1/30+1/42+1/56+1/72+1/90 1/30+1/42+1/56+1/72 简算 1/30+1/42+1/56+1/72简便算法 1/30+1/42+1/56+1/72＝ 简算1/30+1/42+1/56+1/72＝? 1/30+1/42+1/56+1/72= 30分之1+42分之一+56分之1+72分之一 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 1/12+1/20+1/30+1/42+1/56+1/72+1/90 1/12+1/20+1/30+1/42+1/56+1/72+1/90 1/6+1/12+1/20+1/30+1/42+1/56+1/72 简便计算 1/2+1/6+1/20+1/30+1/42+1/56+1/72等于多少? 1/2+1/6+1/20+1/30+1/42+1/56+1/72等于几? 1/6+1/12+1/20+1/30+1/42+1/56+1/72 1/12+1/20+1/30+1/42+1/56+1/72+1/90=? 1/6+1/12+1/20+1/30+1/42+1/56+1/72=?