Q. How can I take a screenshot on the Macs?

To take a screen shot of your entire screen, hold down the Command and Shift keys and press 3.

If you hold down the Command and Shift keys and press 4, Mac OS X turns the cursor into crosshairs you can use to select whatever portion of your display you’d like to capture in a screen shot.

If you immediately hit the Spacebar after typing Command-Shift-4, Mac OS X replaces those crosshairs with a little camera. Using the camera, you can take a screen shot of the Dock, the entire menu bar, a single open menu, the desktop, or any open window.

Instructions provided by Apple, Inc.