[tex]\displaystyle \\
\text{Aflam numarul de termeni.} \\ \\
n=9001-5+1 = 8997 \;termeni \\ \\
Aplical ~formula~lui~Gauss. \\ \\
5+6+7+ ... +9001 = \\ \\
= \frac{8997 (9001+5)}{2} = \frac{8997 (9006)}{2}= \boxed{8997\times 4503} =\boxed{40513491}[/tex]
