Question

\(A=1-2-3+\text{4}+5-6-7+...+2008+2009-2010-2011\)

Answer 1

A = 1 - 2 - 3 + 4 + 5 - 6 - 7 + ... + 2008 + 2009 - 2010 - 2011

A = ( 1 - 2 - 3 + 4 ) + ( 5 - 6 - 7 + 8 ) + ... + ( 2005 - 2006 - 2007 + 2008 ) + ( 2009 - 2010 - 2011 )

A = 0 + 0 + ... + 0 + ( -2012 )

A = -2012

Answer 2

\(A=1-2-3+4+5-6-7+8-...+2005-2006-2007-2008+2009-1010-2011\)

\(< =>A=\left(1-2-3+4\right)+\left(5-6-7+8\right)+...+\left(2009-2010-2011\right)\)

\(< =>A=0+0+...+2009-2010-2011\)

\(< =>A=2009-4021=-2012\)

Answer 3

A = (1 - 2 - 3 + 4) + (5 - 6 - 7 + 8) + ... + (2005 - 2006 - 2007 + 2008) + (2009 - 2010 - 2011)

A = 0 + 0 + ... + 0 + (-2012)

A = -2012

Vậy A = -2012