Đáp án:
Giải thích các bước giải:
=`1/199`+`2/198`+`3/197`+...+`197/3`+`198/2`+`199/1`
= (`1/199+1`)+(`2/198+1`)+(`3/197+1`)+...+(`197/3+1`)+(`198/2+1`)+`200/200`
=`200/199`+`200/198`+`200/197`+...+`200/3`+`200/2`+`200/1`+`200/200`
=200( `1/200`+`1/199`+`1/198`+`1/197`+...+`1/3`+`1/2`)
=200*A
`A/200`=`1/200