Home → Curriculum Hub → Maths Lessons → Schemes of Work → Key Stage 3 → Chance and Probability
This Key Stage 3 Chance and Probability scheme of work brings together the lessons I use when I want students secure on writing and comparing probabilities, listing combined outcomes systematically, and linking theoretical ideas to experimental data. The page sets out what I expect students to bring from earlier fraction work, the ideas I keep coming back to in class, and how this unit fits the wider KS3 probability strand.
Use it as a departmental reference: sequence the lessons below in the order that matches your scheme, adapt timings to your cohort, and cross-link to other units when you need extra practice on fractions or data handling. Everything here describes the unit at a glance—the individual lesson pages hold the presentations, worksheets and tutorials.
Published: March 10, 2023
Last updated: April 2026
For more schemes and topic routes across KS3, GCSE and A-Level, browse the Mr Mathematics Curriculum Hub.
Read the four summary cards first so you know the prior expectations and the language you want students to hear consistently. Then work through the lessons in the order below unless your department timetable needs you to split content across terms—if you do, keep fractional probabilities and comparison on a scale in reach of combined events and experimental work, so vocabulary does not shift lesson by lesson. Jump straight to the lesson list when you are ready to open resources or set cover.
Presentations, worksheets, question generators and video tutorials for the lessons in this unit are available to members. Explore Mr Mathematics membership if you need full access to the library and schemes of work.
Students should arrive with these fraction skills in place before probability work leans on simplified fractional forms and comparison.
These are the ideas I keep explicit while teaching this unit.
How this unit supports fluency, reasoning and problem solving in Key Stage 3.
National curriculum links this unit supports at Key Stage 3 (Probability).
Use it as the map, not the lesson. Check prerequisite knowledge with your classes, align the key concepts with your department’s vocabulary, then teach the lessons in the order that fits your timetable—opening each lesson from its own resource page when you need the presentation or worksheet.
They need confident comparison and manipulation of fractions—including simplifying and related denominators—so probabilities written as fractions are a natural step, not a barrier alongside new vocabulary.
Each lesson in the list below has its own page on Mr Mathematics with downloadable resources and, where available, an online lesson and question generator—access depends on your membership level.
Yes, if your scheme requires it—keep an eye on dependency: students usually need probability as a fraction and comparison on a scale before combined events and expected frequencies feel coherent. If you reorder, re-check the key concepts card so language on outcomes, events and estimation stays consistent across the unit.
Lesson titles as listed on the scheme—open each from the site navigation or search when you are ready to teach.
Students learn how to write probabilities as simplified fractions.
Later, students are challenged to create a series of events for fixed probabilities as learning progresses.
Students learn how to compare the probability of events.
Later, as learning progresses, they compare probabilities using fractions, decimals and percentages.
Students learn how to list all the permutations of two events and calculate their probabilities.
Later, as learning progresses sample space diagrams are introduced for the more able.
Students learn how to predict outcomes using probability.
As learning progresses students understand the effect of sample size in determining the accuracy of the predictions.
Students learn how to estimate probabilities from experimental data to check for bias.
ÂLater, as learning progresses they consider the effect of the sample size and relative frequency.
Students gain additional practice using writing a probability as a simplified fraction.
The problem-solving activity challenges determine the sample size when given a probability.
Students systematically list all possible outcomes for two or more events, starting with coin flips and moving to draws with replacement. They construct sample spaces for spinner combinations and calculate theoretical probabilities.
Later, learners model expected winnings from a fayre game. By calculating long-term profit over multiple plays, students connect permutation listing to decision-making.
Students revise how to write the theoretical probability of an event using fractions.
As learning progresses, they link probability to frequency trees and two-way tables.
A research-backed case exploring why over-reliance on automated math homework platforms and repetitive worksheets lowers student expectations, and how departments can build genuine mathematical thinking.
How to teach converting between fractions, decimals and percentages.
Four problem solving lessons to develop student’s mathematical reasoning and communication skills.
