Most keyboards for desktop Macs contain between 101 and 115 keys that break down as follows . Figure 1-2 shows an example of a fairly typical Mac keyboard.
Twenty-six letter keys for the letters a through z.
A [Spacebar] to put spaces between characters .
Figure 1-2: A fairly typical Mac keyboard layout
Two sets of keys for the single-digit numbers (0 through 9), one set appearing as a row above the letter keys and one set on the numeric keypad. The row of number keys double as symbol keys.
Fifteen to 18 keys for mainstream punctuation symbols (for example, comma, period, and semicolon) and other symbols (for example, + and ~). The numeric keypad typically includes symbols used for basic mathematical operations (+ for addition, - for subtraction, / for division, and * for multiplication) and a period for a decimal place.
A [Tab] key for entering tabs and for navigating from one interface element to another.
A [Return] key and an [Enter] key (on the numeric keypad) for entering carriage returns and clicking the selected button in dialog boxes.
Two [Shift] keys to change the case of the key pressed, and a [CapsLock] key to lock the letter keys in the capital position.
Six modifier keys: two [Ctrl] or [Control] keys, two [Alt]/[Option] keys, and two [ z ] keys (discussed in the next section).
A [DeleteForward] key for deleting the selection or the character after the insertion point, and a [Delete] key for deleting the character before the insertion point.
Eight or more navigation keys: four arrow keys ( , , , and ), a [Home] key for moving to the beginning of an item, an [End] key for moving to the end of an item, a [PageUp] key for moving up by a page of information, and a [PageDown] key for moving down by a page.
Twelve or more function keys, numbered [F1] to [F12] or the appropriate higher number, for invoking functionality built into the operating system and into applications. Some keyboards have 16 function keys.
A [NumLock] key for locking on the numeric keypad.
An [Esc] key for canceling an action or clicking the Cancel button in a dialog box.
Some keyboards have extra keys for increasing and decreasing the playback volume, for toggling muting of all sound, and for ejecting the selected CD or other medium.