Skill: Describe pattern rules

A pattern rule tells how to get from one term to the next. Look for what changes each time.

Example: Find the rule and the next two numbers.

$$4,\ 7,\ 10,\ 13,\ \square,\ \square$$

Step 1: Compare neighboring numbers.

• $4$ to $7$: add $3$
• $7$ to $10$: add $3$
• $10$ to $13$: add $3$

The same change happens each time.

Step 2: Say the rule in words.

The rule is: Add $3$ each time.

Step 3: Use the rule to find the missing terms.

Starting with $13$:

• $13+3=16$
• $16+3=19$

So the completed pattern is

$$4,\ 7,\ 10,\ 13,\ 16,\ 19$$

The pattern rule is add $3$ each time.