Summation is the addition
of a set of numbers; the result is their sum or total. An interim or present total of a summation process is
termed the running total. The "numbers" to be summed may be natural numbers, complex numbers, matrices, or still
more complicated objects. An infinite sum is a subtle procedure known as a series. Note that the term summation
has a special meaning in the context of divergent series related to extrapolation.

- WikipediaSummations are often used in the process of reducing
complex equations in to smaller factors that can be more easily manipulated for operations in calculus and other
mathematical methods.