Final answer:
The method used to establish an expression or procedure for an arithmetic sequence is by adding a common difference to each term.
Step-by-step explanation:
The method used to establish an expression or procedure for an arithmetic sequence is by adding a common difference to each term. This is described in statement C.
For example, consider the arithmetic sequence: 2, 5, 8, 11, 14. The common difference is 3 (adding 3 to each term) and this pattern continues throughout the sequence.