Basic 3 · Mathematics · Patterns and Relationship
Increasing and Decreasing Patterns
In this topic you will describe, continue and create patterns that grow or get smaller.
By the end of these notes you should be able to:
- Describe the rule of a pattern
- Continue increasing and decreasing patterns
- Create your own patterns
What you already know
- Number patterns (Basic 2)
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
- Strand
- Algebra
- Sub-strand
- Patterns and Relationship
- Indicator
- B3.2.1.1.1 – Demonstrate an understanding of increasing and decreasing patterns
Introduction
A savings box has GH₵5 in week 1, GH₵10 in week 2 and GH₵15 in week 3. The amount increases by GH₵5 each week.
1. Increasing Patterns
| Pattern | Rule |
|---|---|
| 5, 10, 15, 20 | add 5 |
| 100, 200, 300, 400 | add 100 |
| 3, 6, 12, 24 | double |
2. Decreasing Patterns
| Pattern | Rule |
|---|---|
| 50, 45, 40, 35 | subtract 5 |
| 1,000, 900, 800 | subtract 100 |
| 64, 32, 16, 8 | halve |
3. Describing a Rule
- Look at the first two numbers.
- Find the difference.
- Check that it works for every step.
- Write the rule in words.
New words
- increasing
- Getting bigger.
- decreasing
- Getting smaller.
- rule
- What is done each time.
- term
- A number in a pattern.
Summary
- Increasing patterns get bigger; decreasing patterns get smaller.
- The rule tells what to do each step.
- Check the rule on every step.
Class activity: Pattern Makers
- Make a pattern with bottle tops or number cards.
- Your partner finds the rule and the next two terms.
- Swap roles.
You need: Bottle tops, Locally made number cards, Exercise books
Exercises
Answer in your exercise book first, then check your answers.
1. What is the rule? 10, 20, 30, 40
- A. Add 10
- B. Add 20
- C. Subtract 10
- D. Double
Show answer
Answer: Add 10Each term is 10 more.2. What comes next? 80, 70, 60, ___
- A. 50
- B. 40
- C. 55
- D. 65
Show answer
Answer: 50Subtract 10.3. 25, 20, 15, 10 is a decreasing pattern.
- A. True
- B. False
Show answer
Answer: TrueIt gets smaller.4. The rule for 7, 14, 21, 28 is add 6.
- A. True
- B. False
Show answer
Answer: FalseThe rule is add 7.5. 300, 400, 500, ______
Show answer
Answer: 600Add 100.6. Write the next two terms: 99, 88, 77, ___, ___
Show answer
Answer: 66, 55Subtract 11.
Homework
- Make a savings plan pattern for 6 weeks. Write the rule.