@Học để làm gì ?
`4/(2.4)+4/(4.6)+4/(6.8)+...+4/(2008.2010)`
`=4/2 . [1/(2.4)+1/(4.6)+1/(6.8)+...+1/(2008.2010)]`
`=2.[(1/2 - 1/4) + (1/4-1/6) +(1/6 -1/8) +....+(1/2008 - 1/2010)]`
`=2.[1/2 - 1/2010]`
`= 2 . [1005/2010 - 1/2010]`
`= 2 . 1004/2010`
`= 2008/2010`
`=1004/1005`
`#Study well`