Construct & interpret picture graphs (one-to-one)
Theory
Picture graphs are a Year 3 way to show data: each category gets a row of pictures, and a key tells you what one picture means. This page explains one-to-one picture graphs, where one picture stands for one thing, and shows how to read a row, find the most and fewest, compare rows, find a total, and construct a graph or a new row from data. In Western Australia one-to-one picture graphs are first taught in Year 2, so this page is revision there. Curriculum: VC2M3ST02 / AC9M3ST02.
A picture graph (also called a pictograph) shows data using pictures. Things are sorted into groups, and each group gets its own row. The pictures in a row are lined up neatly so the rows are easy to compare.
This page uses one-to-one picture graphs. One-to-one means one picture stands for exactly one thing, so \(3\) pictures mean \(3\) things. The key tells you what one picture is worth, for example one circle \(=1\) student. The title says what the graph is about, and each row has a label.
To read a row you count the pictures. To compare rows you look at which has more or fewer pictures and subtract to find the difference. To find a total you add every row. To construct a graph you draw one picture for each thing in the data.
Picture graphs do not need formulas, but these facts hold for every one-to-one picture graph.
How to read a picture graph
- Read the title and the key. Check what the graph is about and what one picture stands for. On a one-to-one graph one picture \(=1\) thing.
- Count each row. Point to each picture as you count so you do not skip or double-count. The number of pictures is the value of that row.
- Answer the question. Longest row for the most, shortest for the fewest. Subtract for "how many more" or "how many fewer". Add the rows for a total, or add two rows for "A or B".
How to construct a picture graph
- Write a title. Say what the graph shows, such as "Pets owned by class 3K".
- Label the rows. Write each category at the start of its own row.
- Draw one picture per thing. Use the same picture, the same size, lined up with equal spacing.
- Add the key. Show one picture and write what it stands for, such as one circle \(=1\) student.
| \(1\text{ circle}\) | \(=\) | \(1\text{ book}\) |
| \(\text{Tue row}\) | \(=\) | \(6\text{ circles}\) |
\(6\) books were borrowed on Tuesday.
| \(\text{Mia}\) | \(=\) | \(6,\ \text{Sam}=5\) |
| \(6 - 5\) | \(=\) | \(1\) |
Mia scored \(1\) more goal than Sam. Sam scored \(1\) fewer goal than Mia.
| \(\text{Choc}+\text{Vanilla}+\text{Berry}\) | \(=\) | \(3 + 5 + 4\) |
| \(3 + 5 + 4\) | \(=\) | \(12\) |
\(12\) cupcakes were sold altogether.
| \(1\text{ sticker}\) | \(=\) | \(1\text{ circle}\) |
| \(9\text{ stickers}\) | \(=\) | \(9\text{ circles}\) |
Draw \(9\) circles, lined up with equal spacing.
(i) How many circles go in Kai's row?
(ii) Who found the most shells now?
(iii) How many shells are shown altogether?
| \(\text{Kai}\) | \(=\) | \(7\text{ circles}\) |
| \(7\) | \(>\) | \(6\) |
| \(5 + 3 + 6 + 7\) | \(=\) | \(21\) |
(i) \(7\) circles.
(ii) Kai, because his row is now the longest.
(iii) \(21\) shells.
(i) On which day were the fewest books borrowed?
(ii) How many books were borrowed on Tuesday or Thursday?
(iii) Is this true: "More books were borrowed on Monday than on Tuesday"?
| \(\text{shortest row}\) | \(=\) | \(\text{Thu } (2)\) |
| \(6 + 2\) | \(=\) | \(8\) |
| \(4\) | \(<\) | \(6\) |
(i) Thursday.
(ii) \(8\) books (add the two rows).
(iii) False: Monday has \(4\) and Tuesday has \(6\), so fewer were borrowed on Monday.
Common pitfalls
Frequently asked questions
What is a picture graph?
A picture graph, or pictograph, shows data using pictures. Each category has its own row, and the pictures in that row stand for the things counted. A key tells you what one picture means.
What does the key on a picture graph mean?
The key tells you what one picture stands for. On a one-to-one picture graph the key says one picture \(=1\) thing, for example one circle \(=1\) book. Always read the key before you count.
How do you read a picture graph?
Read the title and key first, then count the pictures in a row. On a one-to-one graph the number of pictures is the answer. If a row has \(5\) circles and each circle is \(1\) book, then \(5\) books were borrowed.
How do you find the total on a picture graph?
Count the pictures in every row, then add the counts together. If the rows show \(3, 5\) and \(4\), the total is \(3 + 5 + 4 = 12\).
What does one-to-one mean on a picture graph?
One-to-one means one picture stands for exactly one thing. Three pictures mean three things. This is the simplest kind of picture graph.
How do you construct a picture graph?
Write a title, label each category in its own row, then draw one picture for each thing in the data. Line the pictures up with equal spacing and add a key that says one picture \(=1\) thing.