1/2+1/8+1/24+1/48+1/80要简便哦

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1/2+1/8+1/24+1/48+1/80要简便哦
1/2+1/8+1/24+1/48+1/80
要简便哦

1/2+1/8+1/24+1/48+1/80要简便哦
1/2+1/8+1/24+1/48+1/80
=1/1*2+1/2*4+1/4*6+1/6*8+1/8*10
=1/2*(1-1/2+1/2-1/4+……+1/8-1/10)
=1/2*(1-1/10)
=1/2*9/10
=9/20

=1/2+1/2*4+1/4*6+1/6*8+1/8*10
=1/2+(1/2)*(1/2-1/4)+(1/2)*(1/4-1/6)+(1/2)*(1/6-1/8)+(1/2)*(1/8-1/10)
=1/2+(1/2)*(1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10)
=1/2+(1/2)*(1/2-1/10)
=1/2+1/5
=7/10

=1/2+1/4*(1/2+1/6+1/12+1/20)
=1/2+1/4*(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5)
=1/2+1/4*4/5
=1/2+1/5
=7/10

1/2+1/8+1/24+1/48+1/80
=1/2+(1/2)*[(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+(1/8-1/10)]
=1/2+(1/2)*(1/2-1/10)
=1/2+(1/2)*(2/5)
=1/2+1/5
=7/10

2/1+6/1+12/1+24/1+48/1 简便计算：1/8+1/24+1/48+1/120 1/8+1/24+1/48+1/80 1/8+1/24+1/48+1/80简便计算 (1/8+1/15+1/24+1/35+1/48)*2 1/2+1/8+1/24+1/48+1/80要简便哦 1/2 +1/8+1/24+1/48+1/80怎么做简算 8分之1+24分之1+48分之1 8/1+24/1+48/1.2400/1简便计算 8/1+24/1+48/1的简算, (1/8+1/24+1/48+1/80+1/120+1/168+1/224)*64= (1/8+1/24+1/48+1/80+1/120+1/168+1/224)乘64 (1/8+1/24+1/48+1/80+1/120+1/168)简便计算（1/8+1/24+1/48+1/80+1/120+1/168）乘以56 （8/1+24/1+48/1+80/1+120//1+168/1）*42 1/8+1/24+1/48+1/80+1/120+1/168 （1/8+1/24+1/48+1/80+1/120+1/168）*56 42x(8/1+24/1+48/1+80/1+120/1+168/1)=?求求