Question

1+2分之1+6分之1+12分之1+20分之1+30分之1=几,求简便方法 急

Answer 1

1+1/2+1/6+1/12+1/30
=1+1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)
=1+1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=2-1/6
=11/6
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