In the spirit of better investing and in celebration of the first annual Worldwide Invest Better Day (WWIBD) coming up on September 25, Motley Fool analysts will be answering user- and reader-submitted questions leading up to the big event. "Ask a Fool" anything, and we'll do our best to help you invest better.

Gross margin is the amount of profit you have, for each $1 in sales, after deducting all costs directly related to the sale. In the following video, Fool.com analyst Isaac Pino goes over everything that investors need to know about gross margin, including how this metric can provide a useful means for comparison. For example, Apple (AAPL 0.51%) is a company with several different product lines, and looking at gross margin can be a good way of evaluating how they're doing across the board. Watch the video below to learn more.

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