Giải thích các bước giải:
Đặt `A=1/1.11 + 1/2.12 + 1/3.13 + 1/4.14 + 1/5.15 + ... + 1/100.110`
`=> 10A=10/1.11 + 10/2.12 + 10/3.13 + 10/4.14 + 10/5.15 + ... + 10/100.110`
`=> 10A= 1 - 1/11 + 1/2 - 1/12 + 1/3 - 1/13 + 1/4 - 1/14 +1/5 - 1/15 ... + 1/100 - 1/110`
`=> 10A=( 1 + 1/2 + 1/3 + +1/4 + 1/5 + ... + 1/100) - ( 1/11 + 1/12 + 1/13 + 1/14 + 1/15 + .... + 1/110)`
`=> 10A= ( 1+1/2 + 1/3 + ... + 1/10) - ( 1/101 + 1/102 + .... + 1/110)`
`=> A=(( 1+1/2 + 1/3 + ... + 1/10) - ( 1/101 + 1/102 + .... + 1/110))/10`
