Use a rule to complete a number sequence

Key Notes :

Understanding Number Sequences

• A number sequence is a list of numbers arranged in a specific order.
• Each number in the sequence is called a “term.”

Identifying the Rule

Look for a pattern in the given numbers.

Common rules include:

• Addition (e.g., add 3 to each term: 2, 5, 8, 11, …).
• Subtraction (e.g., subtract 4 from each term: 20, 16, 12, 8, …).
• Multiplication (e.g., multiply by 2: 1, 2, 4, 8, …).
• Division (e.g., divide by 2: 32, 16, 8, 4, …).

Steps to Complete a Sequence

• Observe the given terms and find the difference or ratio between them.
• Confirm the rule by applying it to at least two consecutive terms.
• Use the rule to calculate the missing terms.

Common Types of Sequences

• Arithmetic Sequence: A constant number is added or subtracted (e.g., 3, 6, 9, 12, …).
• Geometric Sequence: A constant number is multiplied or divided (e.g., 2, 4, 8, 16, …).
• Mixed Patterns: Combining addition, subtraction, multiplication, or division.

Tips for Solving

• Write the terms neatly to observe patterns clearly.
• Use a table to record differences or ratios.
• If a sequence doesn’t fit a simple rule, consider alternating or repeating patterns.

Learn with an example

Let’s practice!