已知:1-1⼀2=1⼀2,1⼀2-1⼀3=1⼀6,1⼀3-1⼀4=1⼀12,求1*1⼀2+2*1⼀3+3*1⼀4+......99*1⼀100

2024-12-29 10:49:45
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回答1:

1*1/2+2*1/3+3*1/4+......99*1/100
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5++++-1/99+1/99-1/100
=1-1/100
=99/100