2分之1 + 6分之5 + 12分之11 +20分之19 +.+ 99×100 分之9899 求简算

1/2 + 5/6 + 11/12 + 19/20 +。+ 9899/99×100 =(1-1/2)+(1-5/6)+(1-11/12)+(1-19/20)+。+(1-9899/9900)=99-(1/2+1/6+1/12+1/20+。+1/9900)=99-[(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+。+(1/99-1/100)]=99-(1-1/100)=99-99/100=9801/100打字不易,不明白追问哦!