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__Definition.____The definition of the summation process:__

** Summation** is the addition of a set of numbers. The result is their **sum**.

Sums can be represented by the summation symbol, a capital Sigma. This is defined as:

Here, i is the **index of summation**; m is the **lower bound of summation**, and **n** is the **upper bound of summation**.

__Most Commonly Useful Formulas:__

sum of combination of n things taken i at a time (see binomials ) |