The Math Main Idea: how to find the main idea of a number story

February 28, 2024

You’ve heard of the main idea when it comes to reading stories. But it’s not usually something we talk about in math. And I think this is why so many kids struggle when it comes to solving number stories, or math word problems.

I call them number stories because that’s exactly what they are – stories with numbers in them. This is also why I approach solving them as a reading comprehension task. Most teachers will tell you that students not understanding what the problem is asking is one of the biggest barriers to solving number stories.

Today, we’ll explore:

  • How I define the math main idea of a number story
  • Why the math main is idea important
  • How you can help your students determine the math main idea
  • Sample number stories and their main ideas

What is the math main idea?

Dictionary.com defines main idea as “the most important or central thought of a paragraph or larger section of text, which tells the reader what the text is about”.


The math main idea also focuses on what the text is about. In particular, it hones in on the situation that’s occurring within the number story. In Structures of Equality (SoE), I define the math main idea as the action or operation that occurs based on the given situation in a story problem.

Why is the math main idea of a number story important?

A common reason students struggle with number stories is that they approach them procedurally. They either try to solve them as a series of steps to complete, or hunt for keywords or other misleading information.

This often shows up as students picking the number out of a problem, choosing an operation (usually whichever one they worked with last), and solving. Sometimes this works – if they happen to guess right. But it becomes problematic once story problems include extraneous information or multiple steps. 

That’s why the math main idea includes the action or operation. Encouraging students to think about what is happening in a number story, just like they would in any story, helps them grasp the context of the situation occurring within the problem. 

When students can determine the math main idea, they no longer have to “guess and check” or “plug and chug”. They’ll know which operations to choose because they understand the action occurring in the problem.

How you can help your students determine the math main idea

Start by exploring the story itself to help students find the main idea in a number story. An effective way to do this is to be strategic with the questions you pose when introducing a number story. 

It may sound counterintuitive, but at this point, you want to leave off the question in the number story. Start by reading (or having students read) the number story without the question. It’s within the story itself that the action is occurring. By focusing only on the situation, students are more likely to focus on what’s happening and not on ‘answer-getting’.

After reading, pose the following questions:

  • Who are the characters?
  • What’s the setting? (Where is the story taking place?)
  • What are the characters doing?

First, model explaining the math main idea before asking students to do the same. This will help your students figure out what the problem is asking when they do eventually see the question in the number story.

I’ve included some example number stories and their math main ideas to help you get started.

Sample number stories and their math main ideas

Notice how the focus is solely on the situation or action in the story in the examples. To find the math main idea, the question in the number story is irrelevant at this point. Rather than thinking about computation they might need to perform, your students can focus on understanding what is happening in the number story. Once students get the context, they can easily create visual representations to match. Then, they can select strategies and find a solution.

sample number stories and their main ideas

*Stories were taken from the IXL Math site.

You can use these sorting activities to help get started in your classroom. (I usually save the freebies for my email subscribers. If you’d like more resources like these, make sure you sign up below!)

Conclusion

The concept of the math main ideas shifts the focus from a procedural approach to understanding the context and action within a number story. This allows students to gain deeper comprehension of the situations that occur within number stories. Using tools to increase reading comprehension in math helps alleviate the frustration your students face when they don’t know what a number story is asking them to do.

Would you like additional resources about Structures of Equality, including video examples where I model finding the math main idea?

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