MATH · GRADES 6-8 · 40-45 MIN
The Remodel Budget: Percent & Consumer Math lesson plan
Students price flooring for measured rooms, apply a discount and sales tax, and find the break-even area between two options.
At a glance
Time: 40-45 min
Grades: Grades 6-8
Subject: Math: Percent & Consumer Math
Grouping: Teams of 3.
Space: Two rooms per team, any size.
Teacher prep: 15 min printing + 25 min taping
Included: Teacher guide, student sheet, checks for understanding, exit ticket with answers
Open the printable lesson: teacher guide and student sheet →
Essential question
How do percent, area, and unit price combine into a real budget decision?
What students learn and show
Learn: Percent discounts and taxes are multipliers; a fixed fee creates a break-even point between pricing options.
Show: Compute two complete option totals and the break-even area, with work shown.
Objectives
Compute flooring cost from measured area and unit price
Apply a percent discount and then sales tax in the correct order
Compare two options (cheaper material vs. discounted premium) with computed totals
Present and defend a budget recommendation
Before this lesson students should: Percent of a number; area; solving a one-step equation.
Materials and prep
The 1:1 print
Tape measures
Calculators
A price sheet (teacher sets two flooring prices, a discount, and the local tax rate)
Recording sheets
Prep (about 15 min to print, 25 min to tape)
Make the price sheet: Option A $3/sq ft plus a $150 delivery fee; Option B $5/sq ft with 20% off, free delivery; your local sales tax rate (on everything).
Lay out the print or tape two rooms per team.
Copy the budget worksheet.
Space: Two rooms per team, any size.
Grouping: Teams of 3.
Ways to run it: Painter's tape on the floor; 1:1 printed floor plan; Paper only (no floor space needed)
Lesson procedure
Teacher model: Worked example, 200 sq ft, 7.5% tax. A: 200 x 3 + 150 = $750, x 1.075 = $806.25. B: 200 x 5 = $1,000, x 0.8 = $800, x 1.075 = $860. 'Now watch: tax first, then discount: 1,000 x 1.075 x 0.8 = $860. Same total, because multiplying works in either order.'
Guided practice: Teams set up the two option expressions for their room before calculating.
Teams measure their rooms and compute total area to be floored.
Price option A: area x $3 + $150 delivery, then add sales tax. Show every step.
Price option B: area x $5, subtract the 20% discount, then add tax. Test: does tax-then-discount give a different total? (It does not: both are multipliers.)
Compare totals. Which option wins for your rooms? Write each option as an expression and find the break-even area where they cost the same.
Budget pitch: each team recommends one option to the homeowner in 60 seconds, citing totals and the break-even area.
Checks for understanding
Ask: A 200 sq ft room, flooring at $5/sq ft with 20% off: what is the pre-tax cost? Look for: $1,000 minus 20% = $800.
Ask: Add 7.5% sales tax to that $800. Look for: $860.
Ask: Does it matter whether you take 20% off first or add tax first? Look for: Not for the total: both are multipliers (x 0.8 and x 1.075), so the order gives the same result. A fixed-dollar coupon is different.
Exit ticket
Option A costs 3x + 150 and Option B costs 4x (x = square feet, before tax). Find the break-even area. Answer: 150 sq ft (3x + 150 = 4x).
For a 300 sq ft room, which option is cheaper, and by how much before tax? Answer: A: $1,050; B: $1,200; A is $150 cheaper.
Why is there a break-even point at all? Answer: A has a fixed fee but a lower rate; B has no fee but a higher rate, so the lines cross.
Scoring: Items 1-2: 2 points each (setup, answer). Item 3: 1 point. 4-5 secure.
Common misconception
Students may think: Discount-then-tax always costs less than tax-then-discount.
Address it: Test it: with percent discounts and percent tax, both orders give the same total. Only a fixed-dollar coupon changes with order.
Supports and extensions
Learning support: Provide a step-by-step budget template (area → price → discount → tax) with one worked example; assign one room.
Multilingual learners: Pre-teach discount / tax / total with a labeled receipt image; numbers carry the reasoning.
Mobility and access: Measurement can be done by partners or taken from a plan with dimensions; the percent and break-even reasoning stay the goal.
Extension: Add installation labor at a day rate and recompute. Challenge: the homeowner's budget is fixed — work backward to the maximum affordable area and mark it with tape on the plan.
Transfer task: Compare two phone plans: one with a fixed monthly fee and low per-GB price, one with no fee.
Spaced review: A month later: 'Gym A: $20 + $5 per visit; Gym B: $9 per visit. Break-even visits?' (5)
Standards connections
CCSS 6.RP.A.3.c (standard)
CCSS 7.RP.A.3 (standard)
Connections show which skills the activity practices. They are not a claim of full coverage; see the library for scope notes.
Why this approach
Spatial training can improve mathematics performance: g = 0.28 across 29 studies and 3,765 participants aged 3-20, with concrete materials showing stronger transfer than computer-based training. Limit: Average effects across many different programs; this lesson was not among them.
Ready to teach it?
The printable version has the full teacher guide, a student recording sheet, prep steps and an exit ticket. Open the printable lesson →
Need the floor plan itself? Get a 1:1 print quote.
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