=1+(2-3-4+5)+(6-7-8+9)+...+(2010-2011-2012+2013)+(2014-2015-2016)
=1+0+0+...+0+(-2017)
=1+(-2017)
=-2016
A = -1 – 2 + 3 + 4 – 5 – 6 + 7 + 8 – 9 – 10 + 11 + 12 - ... – 2013 – 2014 + 2015 + 2016
A = (0 – 1 – 2 + 3) + (4 – 5 – 6 + 7) + ... + (2012- 2013 – 2014 + 2015) + 2016
A = 0 + 0 + ... + 0
A = 2016
Vậy A = 2016