Luna Park Percent Profits

Overview

This 45-minute Maths lesson helps Year 5 students use percentages to calculate expenses and profit in a business context (Luna Park). Students connect “100% = the whole” to calculating common percentage amounts, then record results in Google Sheets, and finally justify which ride made the greatest profit.

Learning intentions

• WALT use percentages to calculate business expenses and profit.
• WALT calculate common percentages of an amount (e.g., 10%, 20%, 25%, 30%).
• WALT use percentage expenses to find total expenses, then profit (income − expenses).
• WALT record calculations in Google Sheets using correct formulas.

Success criteria

• I can calculate 10%, 20%, 25%, 30% (and related amounts like 5%, 15%) of a money value.
• I can find total expenses by adding the percentage-based expense amounts.
• I can calculate profit by subtracting expenses from income.
• I can enter my results and formulas correctly in Google Sheets.

Curriculum links

• Number — percentages as relative size: recognising 100% as the whole and using percentages to describe, represent and compare relative size.
• Number — connect percentages to decimal and fraction equivalents to support efficient calculation.
• Number — solve practical problems using mathematical modelling, including deciding which operations to use for income, expenses and profit.
• Number — check and explain reasonableness of solutions using estimation appropriate to the context.

Lesson structure (45 minutes)

1. 0–5 min · Mini lesson (explicit teaching). Teacher models “Ferris Wheel earned $120” with expenses as percentages of income (wages 20%, electricity 10%, cleaning 5%), calculates staff wages ($24), electricity ($12), cleaning ($6), total expenses ($42), then profit ($78); students listen and track the steps in their books.

2. 5–10 min · Guided practice (whiteboards). Teacher repeats the same method with “Roller Coaster earned $200: staff wages 25%, electricity 10%, maintenance 15%”, while students calculate each expense, total expenses, and profit on whiteboards; teacher circulates and prompts accuracy (e.g., “What does 25% mean as a portion of 100%?”).

3. 10–40 min · Independent work (modelling + calculation + recording). Students work through the five ride tasks, show calculations neatly, and then enter results into Google Sheets with formulas:

• Dodgem Cars earned $160: staff wages 20%, maintenance 10%, electricity 5% → total expenses and final profit.
• Ferris Wheel earned $240: staff wages 25%, cleaning 5%, electricity 10% → total expenses and final profit.
• Roller Coaster earned $320: staff wages 30%, maintenance 15%, electricity 10% → profit.
• Ghost Train earned $180: staff wages 20%, maintenance 10%, cleaning 5% → total expenses and profit.
• Tea Cups earned $140: staff wages 15%, maintenance 5%, electricity 5% → total expenses and profit. Teacher prompts students to estimate once per task (e.g., “Is profit likely around half the income?”) to support reasonableness checking.

Google Sheets expectation: students create a simple table with columns for income, each expense amount, total expenses, and profit, using formulas for totals and profit (not manual re-entry).

4. 40–45 min · Reflection and share-out. Students answer: “Why don’t businesses keep all of the money they earn?” and one student shares how they used Google Sheets (e.g., “I used a formula for total expenses”). Teacher collects quick checks of one ride’s profit to verify understanding.

Resources

• Whiteboards, markers, erasers (guided step)
• Student workbooks or scrap paper for calculations
• Ride percentage task sheet (five scenarios)
• Access to Google Sheets (one per pair or per student, as your class supports)
• Calculator optional (only for checking; encourage mental/estimation first)
• Base-ten materials or place value grid for students who need a visual bridge from percent to decimals (optional)
• Hundreds chart or fraction/decimal reference cards for support group
• Timers for step transitions

Assessment

• Formative: teacher checks whiteboard calculations for the guided Roller Coaster (spot misconceptions about 25% or 15%).
• Formative: teacher reviews students’ independent work for correct ordering: income → percentage expenses → total expenses → profit.
• Formative: Google Sheets check of formulas (total expenses = sum; profit = income − expenses).
• Quick whole-class check in reflection: students explain why expenses reduce profit (oral or written sentence).

Differentiation

• Support (Enable): teacher focus group uses one ride with simpler percentages (e.g., only 10% or 20% or 50%) and provides a scaffold: estimate first, then compute each percentage using place value (e.g., 20% of $160 is two tenths, so $32). Students can use a place-value/hundreds chart to partition the amount visually.
• Support sentence starters:
• “First I found % of $ = $____.”
• “Total expenses are $____ + $____ + $____ = $____.”
• “Profit is income minus expenses: $____ − $____ = $____.”
• On-task structure: provide a template table in Google Sheets (pre-labelled columns and formula cells) to reduce typing load for students who need it.
• Extension (advanced): after calculations, students compare which ride made the greatest profit and justify using a reasonableness check (e.g., “Even though income was higher, higher expense percentages reduced profit”). Encourage explanation of how changing one expense percentage would affect profit.

Dyslexia-friendly reading options

• Provide the ride scenarios as short, numbered steps with bold headings (Income, Wages %, Electricity %, Maintenance %, Total, Profit).
• Use font size 14–16, high-contrast paper or screen, and lots of spacing between numbers.
• Offer a “read-aloud” option: teacher reads each scenario and students repeat the key percentages and totals before calculating.
• Allow students to underline key information (income amount and each percentage) and use a tracking checklist as they compute.

Extension (optional, teacher-led choice)

• If time allows, students choose one ride and justify a change to increase profit: reduce an expense percentage or increase income, then explain the new profit using calculations.

Reflection prompts

• Why don’t businesses keep all of the money they earn?
• How did Google Sheets help you calculate totals and profit more efficiently?