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1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)...+1/(1+2+3+...100)
=1+2/2*3+2/3*4+2/4*5+...+2/100*101
=1+2*(1/2*3+1/3*4+1/4*5+...+1/100*101)
=1+2*(1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100+1/100-1/101)
=1+2*(1/2-1/101)
=200/101
=1+2/2*3+2/3*4+2/4*5+...+2/100*101
=1+2*(1/2*3+1/3*4+1/4*5+...+1/100*101)
=1+2*(1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100+1/100-1/101)
=1+2*(1/2-1/101)
=200/101
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