How to find the mean
The mean is a kind of average. It’s what each one would be if everything were shared out equally.
- Add up all the numbers.
- Divide by how many numbers there are.
Mean of 4, 6 and 8: 4 + 6 + 8 = 18 → 18 ÷ 3 = 6
The mean doesn’t have to be one of the numbers in the list.
Working backwards
If you know the mean, you can find the total:
total = mean × how many numbers
The mean of 4, 9 and one more number is 6. What is the missing number?
- Total: 6 × 3 = 18
- Numbers you know: 4 + 9 = 13
- Missing number: 18 − 13 = 5
Other averages (good to know)
| Average | Meaning | For 2, 3, 3, 5, 7 |
|---|---|---|
| Mean | total ÷ how many | 20 ÷ 5 = 4 |
| Mode | the most common | 3 |
| Median | the middle one, when in order | 3 |
| Range | biggest − smallest (not an average, but often asked with them) | 7 − 2 = 5 |
Watch out! A score of 0 still counts. Scores of 10, 0 and 8 → 18 ÷ 3 = 6, not 18 ÷ 2.
Top tip: the mean is always between the smallest and biggest number. If your answer isn’t, check your adding!
🎮 Fair sharesQuestion 1 of 5