Communicating
Number - Which Deal Makes Sense?
Teacher Guide
This task requires learners to:
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interpret proportional statements
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compare equivalent and non-equivalent discounts
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justify conclusions using mathematical reasoning
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challenge misleading claims
This is not a speed-calculation task. If learners calculate without explaining why the discounts are equivalent or different, they have missed the point.
Key mathematical ideas
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Equivalence of fractions and percentages
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Guaranteed vs possible outcomes
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Interpreting “up to” in a mathematical context
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Relationship between structure (Buy 2 Get 1) and percentage discount
Progression Continua
Element
Communicating
f
The learner
Uses appropriate mathematical language to describe thinking.
g
The learner
Records and shares mathematical thinking using appropriate representations.
h
The learner
Selects and uses representations to support explanations.
i
The learner
Communicates mathematical thinking clearly and logically.
What learners can typically do in this task
f
The learner
Uses terms such as discount, percentage, fraction, saving and total cost.
g
The learner
Records calculations, tables or annotated workings to show how an offer was analysed.
h
The learner
Chooses representations (e.g. table of costs, fraction-percentage conversions) that clarify equivalence or difference.
i
The learner
Clearly explains and defends conclusions to others and responds to disagreement.
A learner may show different levels across different parts of the task. Judge using best overall evidence, not a single statement.
Teacher Scaffolding Questions Examples Prompts
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“What does ‘up to’ guarantee and what does it not?”
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“Is this discount always the same, or only in this case?”
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“How could you convince someone who believes the biggest percentage is always best?”
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“Can two different-looking offers give the same saving?”
