Question

va rog ajutatima cu acest ex.
1+2+3+4+...+45+46+47+48+49+50=?

Answer 1

1+2+3+...+50=
50*51/2=
25*51=1275
Am aplicat suma lui Gauss.

Answer 2

$\displaystyle 1+2+3+4+...+45+46+47+48+49+50= \\ \\ = \frac{50(50+1)}{2} = \frac{50 \times 51}{2} = \frac{2550}{2} =1275$