Jawabanmu

2014-08-26T16:56:28+07:00
1-2+3-4+5-6+...+99-100
=(1-2)+(3-4)+(5-6)+...+(99-100)
=(-1)+(-1)+(-1)...  Sebanyak 50 pasang
=-50

Maaf kalau sulit dimengerti.
2014-08-26T17:02:17+07:00