Question

Cum sa calculez 1+2+3+4+...+2013? Va mulțumesc!

Answer 1

1+2+3+4+....+2013=$\frac{n(n+1)}{2}= \frac{2013(2013+1)}{2}= \frac{2013*2014}{2}= 2013*1012= 2037156$

Answer 2

$\displaystyle 1+2+3+4+...+2013= \frac{2013(2013+1)}{2} = \frac{2013 \times 2014}{2} = \\ \\ = \frac{4054182}{2} =2027091$