Reading Pictographs

A pictograph is a special chart that uses pictures or symbols to represent data. The most important part of a pictograph is the key. The key tells you what each picture stands for. In many graphs, one picture doesn't just mean '1'; it might represent $2$, $5$, or even $10$ items! This is called scaling. To find the total for a category, you count the number of symbols and multiply by the value in the key. For example, if the key says $1 \text{ star} = 5 \text{ points}$, and you see $3$ stars, you have $3 \times 5 = 15$ points.

Once you can read the totals, you can compare different groups. We often ask 'how many more' or 'how many fewer' one group has compared to another. To solve these, find the total for both groups first, then use subtraction. If Group A has $20$ and Group B has $12$, you calculate $20 - 12 = 8$. You can also compare the symbols directly if they have the same value. If Group A has $2$ more symbols than Group B, and each symbol is worth $5$, then Group A has $2 \times 5 = 10$ more items.

When you make your own pictograph, you have to choose a scale for your key. If you have large numbers like $20, 40, \text{ and } 60$, using a scale of $1$ would take too long to draw! Instead, you might choose $1 \text{ symbol} = 10$. Always remember to give your graph a title so people know what they are looking at, and label each row clearly. Make sure your symbols are the same size and lined up neatly so it is easy to compare them at a glance.