In the below photo of a keyboard, you will find that different function or action keys are either surrounded/enclosed by a red line with a number in red or just have a number in red on top of the key. These red numbers are used below the photo to confirm the name of each key(s) (e.g. 1 =Delete Key).

• 1 = Delete Key
• 2 = Backspace Key
• 3 = Tab Key
• 4 = Return Key
• 5 = Caps Lock Key
• 6 = Shift Key
• 7 = Control Key
• 8 = Function Key
• 9 = Alt Key
• 10 = Space Bar
• 11 = Arrow Keys

easy test: http://www.blairenglish.com/exercises/technology_web/exercises/computers_keyboard_keys1/computers_keyboard_keys1.html