Year 3 Mathematics · AC9M3N07

Follow and create algorithms involving a sequence of steps and decisions to investigate numbers; describe any emerging patterns

An algorithm is an ordered set of instructions. Decisions such as even or odd can change the next step, and recording outputs helps reveal patterns

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Learning goalsSay it simply

An algorithm is an ordered set of instructions. Decisions such as even or odd can change the next step, and recording outputs helps reveal patterns.

Learning routine: Start value → Follow step → Make decision → Repeat → Record pattern

Success looks like

  • Follow steps
  • Use decisions
  • Repeat accurately
  • Create algorithms
  • Describe patterns

Success criteria:

  • Follow steps
  • Use decisions
  • Repeat accurately
  • Create algorithms
  • Describe patterns
Key conceptTeach from the board

Key idea: An algorithm is an ordered set of instructions. Decisions such as even or odd can change the next step, and recording outputs helps reveal patterns.

Learning routine: Start value → Follow step → Make decision → Repeat → Record pattern

algorithm
an ordered set of steps and decisions
decision
a choice that changes the next step
pattern
a regularity that can be noticed and described
Clean visual examplesOne-page board

Clean one-page examples

AC9M3N07 - Follow and create algorithms involving a sequence of steps and decisions to investigate numbers; describe any emerging patterns
Example 1

Start 8 ↓ Is it even? ↓ Yes: divide by 2 ↓ 4 ↓ Repeat ↓ 2 ↓ 1

Example 2

Input Rule +3 then ×2 Output 2 (2+3)×2 10 5 (5+3)×2 16 8 (8+3)×2 22

Example 3

Follow an even-or-odd algorithm Start 8 ↓ Is it even? ↓ Yes: divide by 2 ↓ 4 ↓ Repeat ↓ 2 ↓ 1 Each decision uses the current number, not the starting number. Read every label and identify what each quantity or feature represents. Describe the relationship shown by the model. Check that the conclusion answers the original question.

Example 4

Create an algorithm and test several inputs Input Rule +3 then ×2 Output 2 (2+3)×2 10 5 (5+3)×2 16 8 (8+3)×2 22 Testing several inputs helps identify the pattern in outputs. Apply the same relationship to the new context, then justify the answer using the labels and evidence shown.

Curriculum examplesCopied content

The content description and elaborations below show the curriculum ideas taught in this unit. Items marked as teaching context support lesson planning.

  • Content description: follow and create algorithms involving a sequence of steps and decisions to investigate numbers; describe any emerging patterns
  • E1: following or creating an algorithm to generate number patterns formed by doubling and halving using technology to assist where appropriate; identifying and describing emerging patterns
  • E2: following or creating an algorithm that determines whether a given number is a multiple of 2, 5 or 10, identifying and discussing emerging patterns
  • E3: creating an algorithm as a set of instructions that a classmate can follow to generate multiples of 3 using the rule “To multiply by 3 you double the number and add on one more of the number”; for example, for 3 threes you double 3 and add on 3 to get 9, for 3 fours you double 4 and add one more 4 to get 12 ...
  • E4: creating a sorting algorithm that will sort a collection of 5 cent and 10 cent coins and providing the total value of the collection by applying knowledge of multiples of 5 and 10

Australian, Victorian and NSW alignment retained from the previous page

RegionCurriculumClosest mapping
AustraliaAustralian Curriculum v9.0AC9M3N07 — follow and create algorithms involving a sequence of steps and decisions to investigate numbers; describe any emerging patterns
VictoriaVictorian Curriculum F-10Year 3 Maths: closest match in Number. Use this page as a VIC-aligned practice and worksheet reference.
NSWNSW CurriculumStage 2 Maths: closest content focus for Follow and create algorithms involving a sequence of steps and decisions to investigate numbers; describe any emerging patterns and related outcomes.
Questions and answersWith answers
What is the big idea in this topic?
An algorithm is an ordered set of instructions. Decisions such as even or odd can change the next step, and recording outputs helps reveal patterns.
What routine should I use?
Start value → Follow step → Make decision → Repeat → Record pattern
How do I know I am ready to move on?
You can follow steps, use decisions, repeat accurately, create algorithms, describe patterns and explain how your model or calculation supports the answer.
Practice and reviewReady for practice
  • Changing the order — Algorithms must be followed in the stated sequence.
  • Decision checked once — Recheck the decision whenever the algorithm repeats.
  • Pattern claimed from one input — Test several inputs.

  1. Create a three-step number algorithm and test it with inputs 2 and 5.

  2. A student follows ×2 then +3 as +3 then ×2. Use input 4 to explain the error.

Review hint: Follow the routine “Start value → Follow step → Make decision → Repeat → Record pattern” and use the worked model to check whether your answer is reasonable.

Curriculum alignmentStart here

An algorithm is an ordered set of instructions. Decisions such as even or odd can change the next step, and recording outputs helps reveal patterns.

Learning routine: Start value → Follow step → Make decision → Repeat → Record pattern

Success looks like

  • Follow steps
  • Use decisions
  • Repeat accurately
  • Create algorithms
  • Describe patterns

Success criteria:

  • Follow steps
  • Use decisions
  • Repeat accurately
  • Create algorithms
  • Describe patterns
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