What makes a sequence an arithmetic sequence?

1. Take any term of the sequence and look at how the next one is produced from it. 2. In an arithmetic sequence the same constant is added each time, and that constant is the common difference. 3. The constant may be negative, in which case the terms fall rather than rise. 4. Multiplying by a constant instead would build a geometric sequence. _Source: Siyavula Mathematics Grade 12 (Everything Maths, CC BY 4.0), Chapter 1: Sequences and series_