1/30+1/42+1/56+1/72 简算

来源：学生作业帮助网编辑：作业帮时间：2024/11/05 11:43:46

1/30+1/42+1/56+1/72 简算
1/30+1/42+1/56+1/72 简算

1/30+1/42+1/56+1/72 简算
答案是4/45,把1/30=1/5-1/6,同理,这样互相抵消,就剩1/5-1/9=4/45.

=1/5*6+1/6*7+1/7*8+1/8*9
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9
=1/5-1/9
=4/45

1/30=1/(5*6)
原式=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9=1/5-1/9=4/45

=1/5*6+1/6*7+1/7*8+1/8*9
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9
=1/5-1/9
=4/45

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=?