**Arithmetic Sequence**

An **arithmetic sequence**, also known as arithmetic progression, is a list of numbers or terms that have a definite pattern.

If we take any number on the list, then subtract it by the previous number, the difference is always the same. This constant difference throughout an arithmetic sequence is universally known as the common difference.

If the common difference is a positive number, we have a case of an increasing arithmetic sequence. Similarly, if the common difference is a negative number, then we have a case of a decreasing arithmetic sequence.

- Example of an
**increasing**arithmetic sequence with the common difference of 3:

-1, 2, 5, 8, 11, 14, 17, ...

- Example of a
**decreasing**arithmetic sequence with the common difference of -2:

5, 3, 1, -1, -3, -5, -7, -9, ...