D3: Sigma Notation

From the DfE Mathematics AS and A-Level Content (LINK):

Sigma Notation

D3-01 Sigma Notation: Introducing Sigma Notation

D3-02 Sigma Notation: Writing a Series in Sigma Notation

D3-03 Sigma Notation: Examples of Evaluating Series

D3-04 Sigma Notation: When to Expand Brackets and When Not