Main Idea & Supporting Details — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Sam has a dog. He feeds it every day. He walks it after school. What is the main idea?
A) Sam takes care of his dog.
B) Sam likes school.
C) Sam eats lunch.
D) Sam plays outside.
Feeding and walking are both ways of caring for a pet, so the sentences work together to show that Sam takes care of his dog — that is the biggest thought.
2. Birds build nests. They use twigs and leaves. Baby birds live in the nest. What is the main idea?
A) Leaves fall from trees.
B) Birds build nests for their babies.
C) Twigs are brown.
D) Baby birds can fly.
All three sentences connect around nests — what they are made of and who lives in them — so the main idea pulls those facts together into birds build nests for their babies.
3. Lily loves to read. She goes to the library every week. She reads before bed. Which is a supporting detail?
A) Lily is seven years old.
B) Lily has a brother.
C) She goes to the library every week.
D) Lily likes to swim.
The big idea is Lily loves to read, and going to the library every week is a small fact that proves her love of reading — so it works as a supporting detail.
4. It was raining outside. Tom grabbed his umbrella. He wore his rain boots. What is the main idea?
A) Tom likes boots.
B) Tom has an umbrella.
C) Tom got ready for the rain.
D) Tom went to school.
An umbrella and rain boots are both things people use on a wet day, so these details all connect to the bigger idea that Tom got ready for the rain.
Part B: Fill in the Blank
Write the correct answer on each line.
1. The main idea tells what the passage is mostly about.
The biggest thought in a passage is called the main idea, so the word that goes after main to tell what the passage is about is idea.
2. A supporting detail gives extra information about the topic.
A detail that backs up the main idea is called supporting because it holds up the big thought like a post supports a roof — so supporting fills the blank.
3. To find the main idea, read the whole passage.
A complete piece of reading made up of sentences is called a passage, and you need to read the entire passage to spot the one big thought running through it.
4. Details are facts that support the big idea.
Supporting details are usually true pieces of information that prove the big idea is right, and true pieces of information are called facts.
5. The title of a paragraph helps you guess the main idea.
The name at the top of a passage is the title, and a good title gives a big clue about what the main idea of the paragraph will be.