# Do too much sum! Forget the basics?

Algebra Level 3

This is an easy problem in my school exams that killed most of my friends. Probably they are much concentrated on harder problems. Do you remember the basics?

$\large S_n=(1)(3)+(2)(4)+(3)(5)+...+n(n+2)$

What is the last three digit of $$S_{30}$$?

You may use a calculator.

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