Having difficulty to figure out variables in correlation formula

Question

From where does that "92110000" come from. For what I understood it is the summation of X squared. But that would be 2300² = 453690000?

Answer 1

Brackets matter:

Here $(\sum x_i)^2 =21300^2 = 453690000$

but $\sum (x_i^2) = 921100000$

and you should read the formula $n\sum x^2 - (\sum x)^2$ as $n\sum (x^2) - (\sum x)^2$