tính thuận tiện : m = 2009 x18 + 2008 x 1998 + 1990 / 2007 x 2009 -2007 -2007
tính:
C=2007/2008 x 1/2009 + 2007/2008 : 2009/2008 + 1/2008
Tính : A = 2007 + 2008 x 2009 / 2009 x 2010 - 2011 = ?
Tính : A = 2007 + 2008 x 2009 / 2009 x 2010 - 2011 = ?
2007/2008 x 1/209 + 2007/2008 : 2009/2008+1/2008
2004 x 2007 + 6 / 2005 x 2005 - 2009
(1 + 3 + 5 + .... +2007 + 2009 + 2011 ) x (125125 x 127 - 127127 x 125 )
tìm B = 2021 x 13 + 2009 + 2020 x 2007 / 2020 + 2020 x 520 x 2020
1/3 + 1/6 + 1/10 + 1/15+.........+ 2/ X x (X+1) = 2007/2009