Question

cum se rezova
 1+2+3+...+20?

Answer 1

O safolosesc metoda lui Gauss
(20-1):1+1=19+1=20 (numere)
(20+1)•20 :2=21•10=210 este suma numerelor

Answer 2

$Suma \ \ lui\ \ Gauss\ \ :\ \ \boxed{\boxed{n(n+1):2}} \ \ unde\ \ n=20\ \ in \ \ cazul\ \ nostru \\ \\ 1+2+3+...+20=20(20+1):2=10*21=\boxed{210}$