Question

Calculati suma gauss:
4+5+6+....+118 =
​

Answer 1

 

$\displaystyle\bf\\4+5+6+...+118=?\\Aflam~numarul~de~termeni.\\\\n=118-4+1=114+1=115~termeni\\\\Aplicam~formula~lui~Gauss.\\\\S=\frac{n(118+4)}{2}=\frac{115(118+4)}{2}=\frac{115\times122}{2}=115\times61=7015 \\\\\boxed{\bf4+5+6+...+118=7015}$