Mathematics

Advanced

50 mins

Teacher/Student led

Learning Goals

Learning Outcomes

Lesson Files

+80 XP

What you need:
IWB/Projector/Large Screen

Problem-solving with Discounts and Increases

Work out the final price when a discount or increase is applied, using 10% as a stepping stone. Compare two offers to find the better deal.

Warning: Your screen size is quite small for viewing this. Rotate your device into landscape mode if you can.

1 Getting Started
2 Watch and Notice
3 Try It Together
4 Build the Four-column Row in Your Copy
5 Class Challenge
6 What Did We Notice?
7 What's Next
Pupil practice

1 - Getting Started ~4 mins

Illustration for Getting Started

Key point

You are in a shop and you spot a sale tag: 30% OFF, €50. So what do you actually hand over at the till, and how much did you just save? Take a moment and picture it before we work it out together.

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~10 mins

Three price tags. Each one is built from a single starting fact: 10% is the price divided by ten.

Watch how every percentage is made out of that 10%: two lots of it for 20%, and 10% + 10% + half of 10% for 25%. Predict each answer before you check it.

Watch too how the saving and the price paid always add back to the original, and how the last one grows instead of shrinking.

Three price tags

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~12 mins

Today we work through this short shopping list together, one item at a time: a €60 jacket with 20% off, then a €30 top with 25% off, then a €120 bill with 10% service added, and finally a €80 pair of boots with 15% off. For each item we find the change, then say the final price, and check it makes sense against the original.

Worked example

Here is one worked all the way through, so you can see the moves. Take the €30 top, 25% off: 10% of €30 is €3, halve it for 5% (€1.50), so 25% is €3 + €3 + €1.50 = €7.50. The saving lands on a cent here, €7.50, which is fine. Take €7.50 off €30 and you pay €22.50.

Shopping list

+15 XP

4 - Build the Four-column Row in Your Copy ~3 mins

COPYBOOK MOMENT

In your maths copy, make a four-column row for each item: the original price, the percentage change, the amount of change, and the final price. Box the final price in each row.

€60 jacket, 20% off
€30 top, 25% off
€120 bill, 10% added
€80 boots, 15% off

+10 XP

5 - Class Challenge ~9 mins

Today we'll work through a set of shopping problems together, and they get a little harder each time. First, find the sale price of a €35 game with 30% off, then the saving on a €150 coat with 40% off, then the total after 23% VAT is added to €120 (VAT is a tax added on top of the price — here 23% is added to €120), and finally, here's the tricky one: which is the better deal, 30% off €90 or €70 with 10% added?

Worked example

The VAT one is the biggest step, so here is how we build 23%: 10% of €120 is €12, so 20% is €24. For the last 3%, find 1% first (divide €12 by ten = €1.20), then 3% is 3 × €1.20 = €3.60. Add them: €24 + €3.60 = €27.60 of VAT, giving a total of €147.60.

Shopping challenge

+15 XP

Pupil practice

Module 3 · Fractions, Decimals and Percentages Number

Lesson 40 · Problem-solving with Discounts and Increases

Download Activity Book page (PDF)

123learn · Online learning platform

Unlock the full learning experience

You're previewing this lesson. Get full access to this lesson and hundreds more — each one ready to teach, with interactive activities, printable resources and pupil progress tracking built in.

Hundreds of curriculum-aligned lessons

Interactive activities in every lesson

Printable resources & progress tracking

Get started

Copyright Notice
This lesson is copyright of Coding Ireland 2017 - 2025. Unauthorised use, copying or distribution is not allowed.