Sequences and series

A sequence is essentially an ordered set of numbers. A very simple example of a sequence is 2, 4, 6, 8... A series too is an infinite set of numbers. Series can either be geometric or arithmetic. Geometric series are numbers that are multiplied by a certain number each time. Arithmetic series are similar, but they are just numbers that add or subtract a number each time. A series can have an endpoint and a starting point.