Tap to click = Tap with one finger to click.

Secondary click (right-click) = Click or tap with two fingers.

Smart zoom = Double-tap with two fingers to zoom in and back out of a webpage or PDF.

Scroll = Slide two fingers up or down to scroll.1

Zoom in or out = Pinch with two fingers to zoom in or out.

Rotate = Move two fingers around each other to rotate a photo or other item.

Swipe between pages = Swipe left or right with two fingers to show the previous or next page.

Open Notification Center = Swipe left from the right edge with two fingers to show Notification Center.

Three finger drag = Use three fingers to drag items on your screen, then click or tap to drop. Turn on this feature in Accessibility preferences.

Look up and data detectors = Tap with three fingers to look up a word or take actions with dates, addresses, phone numbers, and other data.

Show desktop = Spread your thumb and three fingers apart to show your desktop.

Launchpad = Pinch your thumb and three fingers together to display Launchpad.

Mission Control = Swipe up with four fingers to open Mission Control.

App Exposé = Swipe down with four fingers to see all windows of the app you're using.

Swipe between full-screen apps = Swipe left or right with four fingers to move between desktops and full-screen apps.