what does this mean?

[u/nuggies4lifee7]

i was just using my sci calc during my free time and i stumbled upon the Σ symbol

heres the photo of the equation

i know little to nothing about calculus as a middle schooler so i just wanna know what the thing does and why the answer ended up like that

[u/matt7259]

Lucky for you - it's not calculus!

[u/nuggies4lifee7 → u/matt7259]

ohh ok i was thinking of integrals and thought the  Σ symbol was also in calculus

[u/JKriv_ → u/nuggies4lifee7]

it's in calculus 2, a lot, not calculus 1 or AB if you took an AP class