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Common Core ELA3rd GradeReading: Informational

RI.3.2: Find the Main Idea and Its Key Details

Also written as CCSS.ELA-LITERACY.RI.3.2 · Cluster: Key Ideas and Details.

All 42 3rd Grade ELA Standards

The Official Wording

Determine the main idea of a text; recount the key details and explain how they support the main idea.

Common Core State Standards, Grade 3, Reading: Informational Text · Read it at the source · Checked October 14, 2026

What RI.3.2 Means in Plain English

Third graders find what a nonfiction text is mostly saying, retell the key details, and explain how each detail backs the idea up. In a passage on Benjamin Franklin, “he invented things to fix everyday problems” is the idea, and the lightning rod and bifocals are the proof.

Second graders (RI.2.2) named the main topic and the focus of each paragraph. Third grade moves from topic to idea, a full sentence the details support. Fourth grade (RI.4.2) adds a written summary, and fifth (RI.5.2) finds two or more main ideas in one text.

RI.3.2 I Can Statements

  • I can tell the main idea of a nonfiction text.
  • I can retell the key details in my own words.
  • I can explain how each key detail supports the main idea.

RI.3.2 Worked Example

The first sentence of this passage is a trap: it is true, but it is not what the rest of the passage is about.

Read the Story
Benjamin Franklin is best known as one of the founders of the United States. He was also an inventor who liked to fix everyday problems.In the 1700s, lightning often set houses and churches on fire. Franklin invented the lightning rod, a pointed metal rod on the roof with a wire running down into the ground. Lightning follows the wire into the ground instead of burning the building.Fireplaces of the time let most of their heat escape. Franklin designed an iron stove that sat out in the room and was meant to give off more heat while burning less wood.As he got older, Franklin needed one pair of glasses for reading and another for seeing far away. Tired of switching, he had the lenses cut in half and joined in one frame, making what we now call bifocals.Franklin was the fifteenth of seventeen children.
A short passage written for this page.
Question: What is the main idea of this passage? Which key details support it, and how?
Not Yet“The main idea is that Benjamin Franklin was one of the founders of the United States.”It comes from the first sentence, but nothing after that sentence is about founding a country. Every detail is an invention, so this cannot be the idea they support.
Meets the Standard“The main idea is that Benjamin Franklin invented things to fix everyday problems. His lightning rod kept lightning from burning buildings. His stove was meant to heat rooms better with less wood. His bifocals meant he didn’t have to keep switching glasses. Each invention solved a problem people had.”The idea is a full sentence that covers the whole passage, and each detail comes with the problem it solved. The fact about his brothers and sisters is left out because it supports nothing.
Question Stems to Use
What is the whole passage mostly about? Say it as a sentence.Is that the topic or the main idea?Does every paragraph fit your main idea? Check each one.Which details support the main idea? How does each one help?Which detail could you leave out? Why?

Common Mistakes with RI.3.2

Naming the topic

“It’s about Benjamin Franklin.”

Try this: Ask “What about Benjamin Franklin?” and have students finish the sentence “Franklin…” so the main idea becomes something the details can prove.

Listing details without the link

“He made a lightning rod. He made bifocals.” with no word about the problems they solved

Try this: Add “which helps because…” after every detail, so students must say how the detail supports the main idea out loud.

Trusting the first sentence

“The main idea is that Franklin helped found the United States.”

Try this: Test the sentence against every paragraph: if most paragraphs say nothing about it, it is true but not the main idea.

Where RI.3.2 Fits

Comes BeforeRI.2.2Name the main topic of a text with several paragraphs and what each paragraph focuses on.
AlongsideRL.3.2Find a story’s central message or moral and explain how key details convey it.SL.3.2Find the main ideas and supporting details of a text read aloud or information shown in a chart or video.
Comes NextRI.4.2Explain how key details support the main idea, then summarize the whole text.

Practice RI.3.2

Quick Check

  1. What is the main idea of the Benjamin Franklin passage?
  2. What problem did the lightning rod solve, and how?
  3. Which detail in the passage does not support the main idea?

RI.3.2: Other Names

RI.3.2CCSS.ELA-LITERACY.RI.3.2

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.