Understand the idea.
Say where to start
A complete rule says where to start and what to do each time. For , say “start at seven and add four each time”. The starting number is already the first number; the first jump makes the second.
Check the instruction
Follow your rule to rebuild the shown numbers. State “add” for forward jumps or “subtract” for backward jumps, and include the jump size. Saying only “gets bigger” leaves many possible patterns, because it does not tell someone the exact change.
See the method in action.
Write a complete rule
Describe 2, 7, 12, 17.
Worked solution
- 1
Identify the starting number.
The first number shown tells where the pattern begins.
- 2
Check each forward jump.
All three jumps add five.
- 3
State both parts of the rule.
Start at two and add five each time; this gives the start and the repeated change.
Start at 2 and add 5 each time.
Follow a rule
Start at 38 and subtract 3 each time. Write the first four numbers.
Worked solution
- 1
Write the starting number first.
Thirty-eight counts as the first of the four numbers requested.
- 2
Make the first two jumps.
Each subtraction gives the next number in order.
- 3
Make the third jump.
Three jumps after the start give four numbers: .
38, 35, 32, 29
Try it yourself.
Check your understanding
Give a full rule for 50, 40, 30, 20.
Show answer & reasoning
Start at 50 and subtract 10 each time.
The first number is fifty, and each jump takes away ten. A full rule is “start at fifty and subtract ten each time”.
Keep practising
6 worksheet questions
Read the questions online
- Describe with a full rule.
- Describe 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 correct?
- Why is get bigger less useful than start at 3 and add 4 each time?
Read the worked solutions
- Describe with a full rule.
The first value is 4 and each jump is .
Start at 4 and add 2 each time. - Describe 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.
- Start at 32 and subtract 2 each time. Write four numbers.
Write the start, then subtract 2 three times.
- A rule says start at 1 and add 10. Is 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 ↗