a)2013-3-6-9-...-99=3(671-(1+2+3+4+...+33)=3(671-33*17)=3*110=330 b)2014-(5+10+15+...+115)=2014-5(1+2+3+..+23)=2014-5*276=634 cd)2014+2013+2012+2011+...4-3+2-1=[(2014-5)+1]*(2014+5)/2+2=2029097 Suma Gauss pt orice sir (ult+primul)*(nr de nr)/2
nr de nr pt orice sir cu regula conservativa : n=(ult-primul)/diferenta dintre doua nr consecutive in sir +1
