Remember that old skimming technique, where you'd read the first and last sentence of a paragraph to glean the main idea? That tried and true college trick is taught to third graders as a way to gather information while they read....

Fourth graders identify the main idea of a sentence using the topic sentence and details of the paragraph. In this main idea lesson plan, 4th graders read paragraphs in the passage Hawaii Quakes, Then Shakes.