Topic, Main Idea, and Supporting Details

Tell apart what a text is about, the point it makes, and the facts that back it up.

Three ideas work together in nonfiction. The topic is the subject, usually a word or short phrase. The main idea is the most important point the author makes about that topic, written as a sentence. Supporting details are the facts, examples, and reasons that prove or explain the main idea. Read this paragraph: 'Octopuses are clever problem solvers.

In aquariums, some have learned to unscrew jar lids to reach food inside. Others have escaped tanks by squeezing through tiny gaps. Scientists have even watched octopuses use coconut shells as portable shelters. ' Topic: octopuses. Main idea: octopuses are clever problem solvers. Supporting details: unscrewing lids, escaping tanks, and using shells.

A quick test is to ask whether each detail helps prove the main idea. Here, every detail does.

• 1The topic is the subject, in a word or phrase.
• 2The main idea is the author's key point, as a sentence.
• 3Supporting details prove or explain the main idea.