What is a number series in math?

Answer 1

A number sequence is an ordered set of numbers. There may be a simple or complicated rule defining the sequence or it may be purely random.

If a1, a2, a3, ... is a number sequence, then define

S1 = a1,

S2 = a1 + a2,

S3 = a1 + a2 + a3,

...

Sn = a1 + a2 + a3 + ... + an , etc

then Sn is a number series.