Question

calculati 1+2+3+.....+180

Answer 1

$\displaystyle 1+2+3+...+180= \frac{180(180+1)}{2} = \frac{180 \times 181}{2} = \frac{32580}{2} =16290$

Answer 2

1+2+3+4.........+180=
=[180*(180+1)]:2       aceasta este suma lui Gauss [n*(n+1)]:2
=180*181:2;
=32580:2
=16290