30/1+42/1+56/1+72/1+90/1=?请写出主要过程.错了.应该是1/30+1/42+1/56+1/72+1/90=?

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30/1+42/1+56/1+72/1+90/1=?请写出主要过程.错了.应该是1/30+1/42+1/56+1/72+1/90=?

30/1+42/1+56/1+72/1+90/1=?请写出主要过程.错了.应该是1/30+1/42+1/56+1/72+1/90=?
30/1+42/1+56/1+72/1+90/1=?
请写出主要过程.
错了.
应该是1/30+1/42+1/56+1/72+1/90=?

30/1+42/1+56/1+72/1+90/1=?请写出主要过程.错了.应该是1/30+1/42+1/56+1/72+1/90=?
是1/30+1/42+1/56+1/72+1/90吧
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)
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1/5-1/10
=1/10

是输入错了吗?这不就是
30+42+56+72+90=290吗??

不会吧？这个还需要过程么？直接相加啊。
290

1/30+1/42+1/56+1/72+1/90
=1/5-1/6+1/6-1/7+1/7+1/8+1/8-1/9+1/9-1/10
=2/10-1/10
=1/10

是1/30+1/42+1/56+1/72+1/90吧等于1/10
＝84/2520+60/2520+45/2520+35/2520+28/2520
＝252/2520
＝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=?