Question

8+9+10+...+95+96+97=?

suma lui Gauss​

Edit:scuze că am pus la limba română m am grabit

Answer 1

 

$\displaystyle\bf\\8+9+10+...+95+96+97=?\\\\Calculam~numarul~de~termeni~(n).\\\\n=97-8+1=89+1=90~de~termeni\\\\Aplicam~formula~lui~Gauss.\\\\S=\frac{n(97+8)}{2}=\frac{90\times105}{2}=45\times105=\boxed{\bf4725}$