To introduce this topic, I displayed a puzzle on the overhead projector – one section at a time. I asked the students to describe what they saw in each of the sections, and to decide if it was a main idea/event or supporting detail/event. The students realized that the sections of the puzzle contained many supporting details, but they could only determine the main idea/event of the puzzle when all of the pieces were put together.
We discussed how this is very similar in reading – good readers put the pieces together in order to understand the main idea/event in the story. The students practiced finding the main idea/event using puzzles, and then applied the skill during independent reading.