Question

3+6+9+12...2019=
Suma lui Gauss

Answer 1

S=3+6+..+12+2019
S=3( 1+2+3+...+673)
S= 3× $\frac{673*674}{2}$
S= 3 ×$\frac{453602}{2}$
S= 3 ×226801
S=680 403

Answer 2

=3(1+2+3+....+673)
=3[(673×674):2]
=3(453602:2)
=3×226801
=680403