Ta có:
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
#Mạt Mạt#
A = (-1 + -5 + -9 +...... + -20130) + (-2 + -6 + -10 + ... + -2014) + ( 3 + 7 + 11 +... + 2015) + (4 + 8 + 12 +.... +2016)
A = -507528 + -508032 + 508032 + 509040
A = 1512
:)))
Ta có: A = - 1 - 2 + 3 + 4 - 5 - 6 + 7 + 8 - 9 - 10 + 11 + 12 - .... - 2013 - 2014 + 2015 + 2016
=(- 1 - 2 + 3 + 4) - (5 + 6 - 7 - 8) - (9 + 10 - 11 - 12) - .... - (2013 + 2014 - 2015 - 2016)
= 4 - (- 4) - (- 4) - .... - (- 4)
= 4 + 4 + 4 + .... + 4
Có 2016 : 4 = 504 nhóm \(\Rightarrow\)A = 504 x 4 = 2016
Vậy A = 2016