a, 2,53 x 2 + 5,06 : 2 x 8 - 10,3 2009 x 2010 + 2000 b, ------------------------------ 2011 x 2010 - 2020

Đáp án:

`a) 2,53 xx 2 + 5,06 : 2 xx 8 - 10,3`

`= 2,53 xx 2 + 2,53 xx 8 - 10,3`

`= 2,53 xx (2 + 8) - 10,3`

`= 2,53 xx 10 - 10,3`

`= 25,3 - 10,3`

`= 15`

`b) (2009 xx  2010 + 2000)/(2011 xx 2010 - 2020)`

`= ((2010 - 1) xx 2010 + 2000)/((2010 + 1) xx 2010 - 2020)`

`= (2010 xx 2010 - 2010 + 2000)/(2010 xx 2010 + 2010 - 2020)`

`= (2010 xx 2010 - 10)/(2010 xx 2010 - 10)`

`= 1`