Question

Buna, poate sa ma ajute cineva?
Calculati 1-2+3-4+5-6+7-8+...+2007-2008+2009-2010
Multumesc!

Answer 1

$1 - 2 + 3 - 4 + 5 - 6 + 7 - 8 + ... + 2007 - 2008 + 2009 - 2010$

$= - 1 - 1 - 1 - 1 - ... - 1 - 1( \times 1005)$

$2010 \div 2 = 1005$

$- 1 \times 1005 = - 1005$