1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42 要简算

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1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42要简算1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42要简算1又1/5+3又1/6+5又

1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42 要简算
1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42 要简算

1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42 要简算
1又1/2+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42
=(1+3+5+7+9+11)+(1/2+1/6+1/12+1/20+1/30+1/42)
=(1+11)×6/2+(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)
=36+1-1/7
=36+6/7
=36又6/7

1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42
=1+1/5+3+1/6+5+1/12+7+1/20+9+1/30+11+1/42
=(1+3+5+7+9+11)+1/5+(1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)
=36+1/5+1/2-1/7
=36+35/70+14/70-10/70
=36+39/70
=36又39/70

1又1/2+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42
=(1+3+5+7+9+11)+(1/2+1/6+1/12+1/20+1/30+1/42)
=(1+11)×6/2+(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)
=36+1-1/7
=36+6/7
=36又6/7能说说第三步哪儿...

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1又1/2+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42
=(1+3+5+7+9+11)+(1/2+1/6+1/12+1/20+1/30+1/42)
=(1+11)×6/2+(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)
=36+1-1/7
=36+6/7
=36又6/7

收起

1又1/5+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42
=(1+3+5+7+9+11)+(1/5+1/6+1/12+1/20+1/30+1/42 )
=(1+11)×3+(1/5+1/2—1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)
=36+(1/5+1/2-1/7)
=36+39/70
=36又39/70
补充1/2—1/3=1/6
1/3-1/4=1/12

=(1+ 1/5)+(3 +1/6)+(5 +1/12)+(7 +1/20)+(9 +1/30)+(11 +1/42)
=(1+3+5+7+9+11)+(1/5 + 1/2 -1/3 + 1/3 -1/4 +1/4 - 1/5 +1/5 -1/6 +1/6 -1/7 )
=36+(1/5 +1/2 -1/7)
=36+39/70
=36又39/70
提示一下1/6 =1/2- 1/3 ,1/12 =1/3 -1/4 。。。。

原式=﹙1+1/5﹚+﹙3+1/6﹚+﹙5+1/12﹚+﹙7+1/20﹚+﹙9+1/30﹚+﹙11+1/42﹚
=﹙1+3+5+7+9+11﹚+[﹙1/6+1/7+1/42﹚+﹙1/20+1/30﹚+1/5﹚]
=30+﹙1/3+1/12+1/5﹚
=30+﹙5/12+1/5﹚=30又37/60