Question # 1: A series is:

1. any list of numbers
2. a summation of quantities whose positions are based upon the natural numbers
3. an arrangement of quantities whose positions are based upon the natural numbers.
Which number is it?

Question # 2: For the rule of 78, for a 12 month period, the last term in the sequence is 12 and the series sums to 78.

For a 14 period, the last term is ? and the series sum is ?.

For a 16 month period, the last term is ? and the series sum is ?.

For a 20 month period, the last term is ? and the series sum is ?.

2 answers

1) a series is an infinite set based on ordered, summed.

2) http://www.college-cram.com/study/businessmath/presentations/781
It is a series of numbers