rule

A rule is a procedure for carrying out a process.

For example, the rule for the following number sequence is ‘multiply by 3 and then subtract 5′:

7, 16, 43, 124, 367, …

In the context of patterns and sequences, words or algebra are used to express a rule.

For example, in the above sequence the next term is three times the present term and then subtract 5. Namely, t_n+1 = 3 × t_n – 5, where t_n represents the present term, and t_n+1 represents the next term.