1/30+1/42+1/56+1/72+1/90

来源：学生作业帮助网编辑：作业帮时间：2024/11/05 11:24:42

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+1/90
1/30+1/42+1/56+1/72+1/90
=1/(5*6)+1/(6*7))+1/(7*8)+)+1/(8*9))+1/(9*10)
=(7+5)/(5*6*7)+(9+7)/(7*8*9)+1/(9*10)
=12/(5*6*7)+16/(7*8*9)+1/(9*10)
=2/(5*7)+2/(7*9)+1/(9*10)
=2*(9+5)/(5*7*9)+1/(9*10)
=28/(5*7*9)+1/(9*10)
=4/(5*9)+1/(9*10)
=(8+1)/(9*10)
=1/10

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=?