Explanation of Sigma notation, also known as Summation Notation. Explanations of how to describe a sum of terms using it, with examples.

## Sigma and Pi Notation (Summation and Product Notation)

Explanation of how Sigma notation describes a sum of terms, with examples. Pi notation, which describes the product of a series of factors, is also introduced. Sum symbol, sum notation, summation notation, product symbol, product notation.