Year 5 Mathematics · AC9M5N09

Use mathematical modelling to solve practical problems involving additive and multiplicative situations including financial contexts

use mathematical modelling to solve practical problems involving additive and multiplicative situations including financial contexts; formulate the problems, choosing…

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Learning goalsSay it simply

Students identify quantities and constraints, choose diagrams, tables or equations, solve multi-step models, test assumptions and communicate recommendations that make sense in the original situation.

A mathematical model preserves the relationships and constraints needed for a decision while simplifying irrelevant detail.

The model must include all travellers, capacity and cost rules. An option that appears cheaper may fail a constraint or require additional units.

Digital tools help compare many scenarios after the formula is understood. State assumptions and test whether reasonable changes affect the recommendation.

Learning routine: Represent → Reason → Calculate → Interpret → Verify

Success looks like

  • Represent the problem
  • Choose an efficient strategy
  • Calculate accurately
  • Interpret the context
  • Estimate or use an inverse to verify
Key conceptTeach from the board

Compare excursion transport options

OptionCapacityFixed costPer personFor 73 peopleA40$120$82 buses: $824B25$70$93 buses: $867constraint73 people + 5 adultsrecalculate capacity

The model must include all travellers, capacity and cost rules. An option that appears cheaper may fail a constraint or require additional units.

  1. Read every label and identify the quantities, parts or evidence.
  2. Explain the relationship shown—not just the final answer.
  3. Check the conclusion against the original question and units.

Use a modelling cycle

understand situation→define quantities/constraints→represent→formulate operations→solve→validate→interpret/recommend

Digital tools help compare many scenarios after the formula is understood. State assumptions and test whether reasonable changes affect the recommendation.

Now transfer the same relationship to a new situation and justify the result with precise vocabulary.

Clean visual examplesOne-page board

Clean one-page examples

AC9M5N09 - Use mathematical modelling to solve practical problems involving additive and multiplicative situations including financial contexts; formulate the problems, choosing operations and efficient calculation strategies, using digital tools where appropriate; interpret and communicate solutions in terms of the situation
Example 1

Option Capacity Fixed cost Per person For 73 people A 40 $120 $8 2 buses: $824 B 25 $70 $9 3 buses: $867 constraint 73 people + 5 adults recalculate capacity

Example 2

understand situation → define quantities/constraints → represent → formulate operations → solve → validate → interpret/recommend

Example 3

Option Capacity Fixed cost Per person For 73 people A 40 $120 $8 2 buses: $824 B 25 $70 $9 3 buses: $867 constraint 73 people + 5 adults recalculate capacity

Example 4

understand situation → define quantities/constraints → represent → formulate operations → solve → validate → interpret/recommend

Curriculum examplesCopied content

Content description: use mathematical modelling to solve practical problems involving additive and multiplicative situations including financial contexts; formulate the problems, choosing operations and efficient calculation strategies, using digital tools where appropriate; interpret and communicate solutions in terms of the situation.

  • E1: modelling an everyday situation and determining which operations can be used to solve it using materials, diagrams, arrays and/or bar models to represent the problem; formulating the situation as a number sentence and justifying their choice of operation in relation to the situation
  • E2: modelling a series of contextual problems, deciding whether an exact answer or an approximate calculation is appropriate; explaining their reasoning in relation to the context and the numbers involved
  • E3: modelling financial situations such as creating financial plans; for example, creating a budget for a class fundraising event, using a spreadsheet to tabulate data and perform calculations
  • E4: investigating how mathematical models involving combinations of operations can be used to represent songs, stories and/or dances of First Nations Australians
Questions and answersWith answers

Core idea: A mathematical model preserves the relationships and constraints needed for a decision while simplifying irrelevant detail.

Remember

  • Represent the problem
  • Choose an efficient strategy
  • Calculate accurately
  • Interpret the context
  • Estimate or use an inverse to verify

Important questions

  • Identify a constraint. Explain using the model or evidence above.
  • Choose a representation. Explain using the model or evidence above.
  • Write a multi-step equation. Explain using the model or evidence above.
  • Validate a recommendation. Explain using the model or evidence above.
  • State one assumption. Explain using the model or evidence above.
Practice and reviewReady for practice
  • All numbers used automatically — Select only relevant quantities and relationships.
  • Constraint checked after recommendation only — Build constraints into the model.
  • Tool output accepted without formula check — Explain cells, operations or equations.
  • Final number lacks interpretation — State what should be done and why.

Learn from the Topic Guide and fixed Teacher Slides, complete the Practice Sheet, use Practice for supported feedback, then take the Test when ready.

Curriculum alignmentStart here

Students identify quantities and constraints, choose diagrams, tables or equations, solve multi-step models, test assumptions and communicate recommendations that make sense in the original situation.

A mathematical model preserves the relationships and constraints needed for a decision while simplifying irrelevant detail.

The model must include all travellers, capacity and cost rules. An option that appears cheaper may fail a constraint or require additional units.

Digital tools help compare many scenarios after the formula is understood. State assumptions and test whether reasonable changes affect the recommendation.

Learning routine: Represent → Reason → Calculate → Interpret → Verify

Success looks like

  • Represent the problem
  • Choose an efficient strategy
  • Calculate accurately
  • Interpret the context
  • Estimate or use an inverse to verify
Teach & ExplainTeaching slides and samples

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Classroom sequence

Teach: translate a situation into quantities and operations. Model: repeated cost plus a fixed fee. Ask: which words signal equal groups? Guided try: write two possible expressions and compare. Misconception check: do not combine a fixed fee inside every group. Independent try: interpret the answer with units.