Pictographs with scale
A pictograph (or pictogram) uses icons to show how big each value is. In Year 2 every icon was worth one — six 🍎 meant six apples. In Year 4 the chart needs to show much bigger numbers, so each icon is worth more than one. The number is written in a small box at the bottom called the key.
Reading the key
The key tells you the value of one icon.
🍎 = 10
Now every full icon in the chart counts for 10. A row with five icons stands for 5 × 10 = 50.
A pictograph can use any key the designer chose: 2, 5, 10, 50 or even 100. Always read the key first.
Half-icons
When the value isn't a whole multiple of the key, the chart shows half an icon (or sometimes a quarter).
Key: 🍎 = 10. Row: 🍎 🍎 🍎 ½
Full icons: 3 × 10 = 30. Half icon: ½ × 10 = 5. Row total: 35.
Key: ⭐ = 50. Row: ⭐ ⭐ ½
Full stars: 2 × 50 = 100. Half: ½ × 50 = 25. Row total: 125.
Some charts also use a quarter or three-quarters of an icon. The same idea applies — multiply the fraction of the icon by the key.
A worked example
Number of trees planted in five years:
Key: 🌳 = 5
| Year | Icons | Trees |
|---|---|---|
| 2020 | 🌳🌳🌳 | 15 |
| 2021 | 🌳🌳🌳🌳 ½ | 22 |
| 2022 | 🌳🌳🌳🌳🌳🌳 | 30 |
| 2023 | 🌳🌳🌳 ½ | 17 |
| 2024 | 🌳🌳🌳🌳🌳 ½ | 27 |
Now answer:
Q. How many trees were planted in 2022?
6 × 5 = 30 trees.
Q. How many more trees in 2024 than in 2023?
27 − 17 = 10 trees.
Q. In which year was the number of new trees exactly twice the number in 2020?
2020 had 15. Twice that is 30. That's 2022.
When the icon represents something logical
Designers often choose an icon that matches the data:
- 📚 for books borrowed,
- 🚗 for cars sold,
- 🎂 for birthdays,
- 🏆 for trophies won,
- 🌧️ for rainy days.
The icon doesn't change the maths — you still multiply icons by the key.
Common mistakes
- Forgetting to multiply by the key. Five icons isn't five — it's 5 × key.
- Misreading half-icons. Half an icon equals half the key, not "half a small number".
- Counting icons wrong when there are many in one row. Group them in fives mentally, like with a tally chart.
What's next
- Bar charts with bigger scales — same scale idea, different chart
- Line graphs — change over time
- Back to the introduction