Question

S999=1+2+3.............+999

Answer 1

se foloseste suma gaus(nu stiu sigur cum se scrie): 1+2+3+...+n=[n x (n+1)] : 2.
1+2+3+...+999=[999 x (999+1)] : 2=999000 : 2=499500.
DECI, 1+2+3+...+999=499500
SPER CA TE-AM AJUTAT!

Answer 2

$\displaystyle 1+2+3+...+999= \frac{999(999+1)}{2} = \frac{999 \times 1000}{2} = \frac{999000}{2} =499500$