Mathematical Sequences Worksheets - Math Worksheets Center Every number in the sequence series is known as a term, member, or element. The next step is to find what the pattern is, or what rule is being used in the given sequence. For example; 2, 4, 6, 8, 10, 12, ... The dots at the end of the sequence means that the sequence is infinite. In the example, the pattern used are even numbers.