Reading · Grade 3 Reading
Chapter 1: Main Idea and Details
The one idea that fits every sentence in a part.
The main idea is the one idea that fits every sentence. Today you learn to test it.
Today’s story
What a Beaver Does to a River
An article, in five parts. About 240 words.
Read one page. Then answer the question in the yellow box.
Page 1 of 4
Teeth like chiselsA beaver’s front teeth never stop growing. They are orange, and the fronts are harder than the backs. As the beaver chews wood, its teeth wear into a sharp edge, like a chisel. A beaver can cut down a tree as thick as your leg in one night.
Why is “a beaver can cut down a tree in one night” not the main idea?
Page 2 of 4
Building the damThe beaver does not eat most of the wood. It drags the branches into the stream. It pushes them together into a wall. It packs the gaps with mud and stones until the water cannot get through. This wall is called a dam.
Page 3 of 4
The pond appearsBehind the dam, the stream stops running and spreads out. In a few weeks, there is a pond where the narrow stream used to be. The beaver builds its home, called a lodge, in the middle of the pond. The door is underwater, so no fox can follow it inside.
Page 4 of 4
Who else moves inThe pond is not only for beavers. Frogs lay their eggs in the still water. Herons stand in the shallow water and catch fish. Dragonflies hunt over the pond, and moss grows on the drowned trees. Before, only a few kinds of animals lived along the stream. Now dozens of kinds live there.
And then a meadowOne day the beavers move away, and the dam breaks. The pond drains, and a flat bed of rich mud is left behind. Grass grows there first, then flowers, then young trees. The place that was a stream, and then a pond, becomes a meadow.
Answer all the questions to open the whole story.
Finish the story first. Then write two things you noticed.
Main idea is usually assessed by agreement with an answer key, which teaches a child to guess the teacher rather than read the text. The two tests here can be run by the child alone: a main idea covers every sentence in the paragraph, and it does not cover paragraphs it has nothing to do with.
When your child names a main idea, ask them to check it against each sentence in turn. The checking is the lesson.