A pattern rule is a mathematical relationship used to find the value of each term in a sequence. It is a description of the pattern core, which is the smallest part of a pattern that repeats. A pattern can be made by numbers or shapes, and if a series of numbers or shapes are repeated with a rule or multiple rules, it forms a math pattern. To find the rule in a pattern, you need to observe the common change in the shapes or numbers. The pattern can be increasing or decreasing, and you can find the sum or difference between the terms to find the rule. Finding the rule for a pattern involves solving an equation that describes the pattern. A numerical pattern is a sequence of numbers that has been created based on a formula or rule called a pattern rule.