Question

(-1)+3+(-5)+7+(-9)+11……+(-2007)+2009

Answer 1

(-1)+3+(-5)+7+(-9)+11……+(-2007)+2009

=-1+3 -5+7 -9+11..-2007+2009

=2+2+2+2+2+2+2+2+2+2+2++2+2+2+.+2

=502*2

=1004

(1/1X3)+(1/2X5)+.+(1/2003X2005)

=1002/2005

(1/1X4)+(1/4X7)+(1/7X10)+.(1/2002)X(1/2005)

=668/2005