Question

Calculati suma : 2+4+6+8+...+20

Answer 1

2 + 4 + 6 + 8 +  ....+ 20 = 2(11 * 10/2) = 11 * 10 = 110
suma lui Gauss

Answer 2

=2(1+2+3+...+10)=$\not2_1\cdot\frac{10\cdot11}{\not2_1}=10\cdot11=110$