<p>How do I know what the upper and lower bounds of my sums should be? I find that I’ll be one off due to misunderstanding the semantics of the problem (IE not knowing the upper bound [AKA the thing on top of the sigma] should be non-inclusive). How do I know when to make the lower bound (AKA the thing below the sigma) 0 or 1, and when making the upper bound the thing that I’m summing to or the index that I’m summing to? Sorry if this is confusing. It’s hard to explain. </p>
<p>Upper and lower indices are inclusive; e.g. \sum_{i=3}^6 i^2 = 3^2 + 4^2 + 5^2 + 6^2 = 86.</p>