Why Do We Use Graphs?
People have been drawing pictures to show numbers for a very long time! Long before computers, people needed ways to compare information quickly. A graph is a picture that shows data (numbers and facts) so you can understand them at a glance.
Think about it this way. If your teacher asked, "Which lunch is the most popular?" you could count every vote. But a bar graph lets you SEE the answer right away! That is the power of graphs.
On the ISEE, you will see graphs and need to answer questions about them. The big question is: can you find totals (adding numbers together) and differences (subtracting one number from another)? Let's learn how!
Key Ideas for Reading Graphs
Before we dive into practice, let's learn the important parts of a graph. These ideas will help you answer every graph question on the ISEE.
Read the Title
Check the Labels
Read the Scale
Find the Values
Do the Math
See It! A Bar Graph Example
Let's look at a bar graph together. This graph shows how many books four students read during summer break. Study it carefully!
Notice how the tallest bar belongs to Ben. That means Ben read the most books. The shortest bar belongs to Cara, so she read the fewest. You can see this just by looking at the heights!
The Math: Finding Totals and Differences
Once you read the numbers from a graph, you need to do simple math. There are two main types of questions you'll see on the ISEE.
Let's use the book graph from above. If the question asks, "How many books did Ana and Cara read altogether?" you would add: 6 + 4 = 10 books.
If the question asks, "How many more books did Ben read than Cara?" you would subtract: 8 − 4 = 4 more books.
Picture Graphs and Their Keys
Not all graphs use bars. A picture graph (also called a pictograph) uses small pictures or symbols to show data. Each picture stands for a certain number. The key tells you what each picture is worth.
Here is the most important thing about picture graphs: always check the key first! If each picture equals 2, you must multiply the number of pictures by 2. If each picture equals 5, you multiply by 5.
A common mistake is forgetting the key and just counting pictures. If you count 5 apples in Room A's row, the answer is NOT 5. It's 5 × 2 = 10. Don't fall into that trap!
Worked Example: Step by Step
Let's solve a problem together using the "Books Read During Summer Break" bar graph from Section 3. Here's the question:
Comparing Different Types of Graphs
On the ISEE, you might see different kinds of graphs. Let's compare the three main types so you know what to expect.
| Graph Type | What It Looks Like | How to Read It |
|---|---|---|
| Bar Graph | Tall or short bars side by side | Match the top of each bar to the number on the scale |
| Picture Graph | Rows of small pictures or symbols | Count the pictures and multiply by the key value |
| Table | Numbers organized in rows and columns | Find the row and column you need, then read the number |
ISEE Test-Taking Strategies for Graph Questions
Knowing the math is important. But on test day, using smart strategies can help you answer faster and avoid mistakes. Here are some tips just for graph questions.
| Strategy | What To Do |
|---|---|
| Read the question FIRST | Before studying the whole graph, read the question. Then you know exactly which bars or pictures to focus on. You save time! |
| Eliminate wrong answers | If you can tell a bar is around 6, cross out any answer choice that is way too big or too small. Then choose from what's left. |
| Check the scale | Don't assume the scale counts by 1s. It might count by 2s, 5s, or 10s. Reading the wrong scale is the most common mistake! |
| Always answer | There is NO penalty for wrong answers on the ISEE. If you're unsure, make your best guess. Never leave a question blank! |
Practice Problems
Now it's your turn! Use the graph below to answer Problems 1 through 4. Problem 5 uses a different graph described in the question. Read carefully, and you've got this!
Let's Review What You Learned!
Great work making it through this lesson! You learned how to read bar graphs and picture graphs by checking the title, labels, and scale first. For picture graphs, always multiply the number of symbols by the key value before doing anything else.
To find a total, add the values together — look for clue words like "in all," "combined," or "altogether." To find a difference, subtract the smaller number from the bigger number — look for "how many more" or "how many fewer." On test day, remember to read the question first, eliminate wrong answers, and never leave a question blank. You've got this!