Mathematics · Year 6 · Financial Mathematics · Term 4

Best Buys and Unit Pricing

Comparing prices and using unit pricing to determine the best value for money.

• ACARA Content Descriptions
• AC9M6N08

About This Topic

Best buys and unit pricing equip Year 6 students with practical skills to compare product costs and find the greatest value. They calculate unit prices, such as dollars per 100 grams or per litre, by dividing total cost by quantity. For instance, students might compare a 400g jam jar at $3.20 with a 750g jar at $5.50, determining the cheaper option per gram. This content from Financial Mathematics in Term 4 aligns with AC9M6N08, where students use multiplication and division in authentic consumer contexts.

The topic fosters financial literacy by having students justify choices, compare multiple sizes, and build shopping lists that prioritize value for household items. It reinforces decimal operations, fractions, and proportional reasoning, skills that extend to budgeting and data analysis in later years. Real-world application helps students see mathematics as a tool for everyday decisions.

Active learning shines here because students handle actual supermarket catalogues or apps to compute and debate unit prices. Group shopping simulations turn calculations into lively discussions, where they defend selections and negotiate trade-offs. This approach makes concepts immediate and relevant, improving accuracy and confidence in financial reasoning.

Key Questions

1. Justify why unit pricing is a valuable tool for consumers.
2. Compare different product sizes to determine the best buy using unit pricing.
3. Design a shopping list that prioritizes best buys for common household items.

Learning Objectives

• Calculate the unit price for various product sizes and quantities to determine the best value.
• Compare the unit prices of different brands and sizes of common household items to identify the most economical option.
• Justify the selection of specific products for a shopping list based on unit price analysis.
• Critique advertising claims about product value by applying unit pricing calculations.
• Design a budget-friendly shopping list for a family meal, prioritizing items with the lowest unit cost.

Before You Start

Decimal Multiplication and Division

Why: Students need to be proficient with decimal operations to accurately calculate unit prices.

Fractions and Ratios

Why: Understanding how to represent and compare parts of a whole is foundational for comparing different quantities and prices.

Key Vocabulary

Unit Price	The cost of a product per standard unit of measurement, such as per kilogram, per litre, or per item.
Best Buy	The product that offers the most value for money, typically identified by having the lowest unit price.
Consumer	A person who purchases goods and services for personal use.
Quantity	The amount or number of a particular product available or contained within a package.

Watch Out for These Misconceptions

Common Misconception

The bigger package is always the best value.

What to Teach Instead

Students often assume larger sizes save money without checking unit prices, leading to poor choices. Hands-on comparisons with real products or flyers reveal counterexamples, like a 1kg pack costing more per gram. Group debates help them articulate why unit pricing trumps size alone.

Common Misconception

Unit price is calculated by subtracting costs instead of dividing.

What to Teach Instead

Confusion arises from mixing subtraction with division in pricing. Station activities with step-by-step guides and peer checks clarify the formula: total cost divided by quantity. Visual aids like number lines reinforce the process during rotations.

Common Misconception

All unit prices must use the same quantity, like per 100g.

What to Teach Instead

Students mix units, such as grams versus millilitres. Catalogue hunts in small groups emphasize consistent units for fair comparisons. Collaborative charting exposes errors, building precision through discussion.

Active Learning Ideas

Supermarket Simulation: Best Buy Hunt

Distribute Woolworths or Coles catalogues to small groups. Each group selects three categories like cereal or toothpaste, calculates unit prices for two sizes per item, identifies the best buy, and justifies with calculations. Groups present one choice to the class for peer feedback.

45 min·Small Groups

Shopping List Challenge

Provide students with a family shopping list budget. In pairs, they research online supermarket sites for five items, compute unit prices, select best buys, and adjust the list to stay under budget. Pairs share their optimized lists.

50 min·Pairs

Product Comparison Stations

Set up stations with props like canned soups or juice bottles of varying sizes. Pairs rotate through four stations, calculate unit prices using calculators, record findings on charts, and vote on class best buys at the end.

40 min·Pairs

Design Your Own Best Buy

Small groups invent household products with sizes and prices, then swap with another group to calculate unit prices and determine the best value. Groups refine designs based on feedback to create unbeatable deals.

35 min·Small Groups

Real-World Connections

• Supermarket managers use unit pricing data to set competitive prices and plan promotions, ensuring their store offers good value to shoppers in suburbs like Parramatta.
• Families planning their weekly grocery shop, for example, parents in Brisbane deciding between different cereal box sizes, use unit pricing to make their budget stretch further.
• Food manufacturers consider unit pricing when designing packaging sizes, aiming to offer competitive value against rival products on supermarket shelves across Australia.

Assessment Ideas

Quick Check

Provide students with two different sizes of the same product (e.g., 500g bag of rice for $4.00, 1kg bag for $7.00). Ask them to calculate the unit price for each and write which is the best buy and why.

Discussion Prompt

Present students with a scenario: 'You need to buy laundry detergent. Brand A is $6.00 for 1 litre. Brand B is $10.00 for 2 litres. Brand C is $4.50 for 750ml.' Ask: 'Which is the best buy? How do you know? What other factors might you consider besides price?'

Exit Ticket

On an exit ticket, ask students to explain in their own words why unit pricing is a useful tool for shoppers. They should include one example of how they might use it when buying groceries.

Frequently Asked Questions

How do you teach unit pricing in Year 6 maths?

Start with simple examples using classroom props, like comparing apple packs: divide cost by count or weight to get price per unit. Progress to supermarket flyers where students calculate for varied products. Emphasize the formula and real decisions, linking to AC9M6N08 through justified shopping lists. Regular practice with decimals builds fluency.

What are common mistakes in best buys activities?

Pupils frequently pick by total price or package size, ignoring unit costs, or miscalculate divisions. They might compare unlike units, like grams to litres. Address with guided worksheets first, then peer-reviewed calculations in groups. Visual scales showing value per unit clarify comparisons effectively.

How can active learning help students master best buys and unit pricing?

Active methods like supermarket simulations with catalogues engage students in authentic calculations and debates, making division meaningful. Rotating stations or pair challenges provide repeated practice with feedback, reducing errors in decimal work. Role-playing shoppers builds justification skills, as they defend choices under budget constraints, boosting retention and real-world application.

Why is unit pricing valuable in the Australian Curriculum?

AC9M6N08 requires applying maths to financial contexts, and unit pricing teaches consumer savvy amid rising costs. Students learn to compare Coles specials or Aldi deals, fostering lifelong budgeting habits. It integrates number skills with critical thinking, preparing them for Year 7 statistics and probability in personal finance.