Maths · KS3 and GCSE · Interactive lesson
Mean, median, mode and range
Change a small data set. Share totals, order values and count repeats to understand what each summary tells you.
Choose your view
Explore an interactive example, then try the questions at your own pace.
KS3 / GCSE · start with the idea
By the end of this lesson: Find and explain the mean of a small data set.
The interactive diagram and controls are in Stage 2, “Explore one example”. Read the idea here, then try it next.
- Mean = total ÷ number of values.
- The mean is the value each item would have if the total were shared equally.
- Every value contributes to the total used for the mean.
Useful starting points
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What do the words mean?
- Mean
- The total shared equally between all the values.
- Median
- The middle value of an ordered list, or the mean of its middle two values.
- Mode
- The value or values occurring most often; if none repeats, there is no mode here.
- Frequency
- How many times a value appears in the data.
- Range
- Largest value minus smallest value. It describes spread, not an average.
- Outlier
- A value that lies unusually far from the others in its context.
Change the example
This is the lesson example. Your practice question uses its own numbers.
Something to try
Change just the orange value. Compare the ordered list and the result. Why does this measure change, or stay the same?
Notice what changes
How particle motion works +
Starts paused. Press Play, then add energy to see the warmer particles move faster.
Particles keep the same size. Liquid particles move around; solid particles vibrate around fixed positions. This is a simplified model, with the change in motion exaggerated to make it easier to see.
About the playback +
About this model
The bars show individual values, not a frequency table; their vertical scale stays fixed. Orange marks the value you can change. A mean or median need not be a value in the original list.
More about this diagram
Still picture. Play particle motion in Stage 2.
Mean: 6
Still picture of the example from Stage 2. Use the back arrow to change it.
Work through it
Starting example: read the steps below
- Add all 5 values: 2 + 4 + 6 + 8 + 10 = 30.
- There are 5 values, including any zeros.
- Share the total equally: 30 ÷ 5 = 6.
- Check: 6 × 5 = 30.
Try on your own
Your turn. No rush.
Question 1
Find the mean of these 5 values: 12, 0, 7, 5, 1.
About these questions
Questions appear in a mixed order. Work at your own pace and stop whenever you like.
These questions use their own numbers, separate from the lesson example. You can stop whenever you like. Answers last for this visit to the page.
A good place to pause
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Can you explain how to find the mean and what it tells you about the list?
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Notes for parents and tutors
These lessons cover selected KS3 and GCSE ideas for England; they are not a complete course. The level notes explain where GCSE methods or optional extensions begin. Maurice can help you choose material for your course and exam board.
The content draws on the DfE Maths curriculum, DfE Science curriculum and AQA GCSE Physics specification. Level labels are guidance, not exam-board endorsements. For AQA Radioactivity, calculating net decline as a ratio is Higher-tier work. Net means the overall change; ask Maurice whether this extension is relevant to your course. Explanations and practice were reviewed during development on 21 October 2026; Maurice should check their fit before assigning work.
Topic labels and your lesson-view preference are saved in this browser. This tab also remembers the last lesson stage, so you can choose to continue there. If you choose revision, selected activities and suggested revisit dates are saved here too. Recent question codes are also kept to reduce repeats. Reflection notes are saved automatically per topic when you type them; you can delete a note in the recap. They stay in this browser and are visible to other people using it. Practice answers and enquiry details are not saved. Clearing browser data removes the labels.
