The idea, step by step
Say where to start
A useful rule tells the starting number and what to do each time. For 7, 11, 15, 19, say: start at 7 and add 4 each time. Saying only add 4 does not tell someone where to begin.
Check the instruction
Follow your own rule to rebuild the given numbers. For a decreasing pattern, use subtract. A rule should describe the jumps between numbers, not merely say that the numbers get bigger or smaller.
A common trap
Applying the step before writing the starting number.
Instead: The start is the first term. Write it, then make the jumps.
See the thinking
Write a complete rule
Describe 2, 7, 12, 17.
- The first number is 2.
- Every jump is 5 more.
Follow a rule
Start at 38 and subtract 3 each time. Write the first four numbers.
- The starting number counts as the first number: 38.
- Subtract 3 successively: 35, 32, 29.
Check your understanding
Give a full rule for 50, 40, 30, 20.
Show answer
Start at 50 and subtract 10 each time.
The starting value and each backward jump are both included.
Your turn
6 questions · Work at your own pace.
Read the questions online
- Describe 4, 6, 8, 10 with a full rule.
- Describe 25, 20, 15, 10 with a full rule.
- Start at 6 and add 3 each time. Write four numbers.
- Start at 32 and subtract 2 each time. Write four numbers.
- A rule says start at 1 and add 10. Is 1, 11, 21, 31 correct?
- Why is get bigger less useful than start at 3 and add 4 each time?
Read the worked solutions
- Describe 4, 6, 8, 10 with a full rule.
The first value is 4 and each jump is +2.
Start at 4 and add 2 each time. - Describe 25, 20, 15, 10 with a full rule.
Every next number is 5 less.
Start at 25 and subtract 5 each time. - Start at 6 and add 3 each time. Write four numbers.
Write the start, then add 3 three times.
6, 9, 12, 15 - Start at 32 and subtract 2 each time. Write four numbers.
Write the start, then subtract 2 three times.
32, 30, 28, 26 - A rule says start at 1 and add 10. Is 1, 11, 21, 31 correct?
Each step adds 10 from the stated start.
Yes. - Why is get bigger less useful than start at 3 and add 4 each time?
A precise rule lets another person make the same pattern.
It does not say where to start or how much to add.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics
Constant increases/decreases; describing rules; missing terms; shape/number patterns.
Official curriculum source ↗