To turn the Numlock function on and off, hold down the fn key and press the F6 key. This key also normally has the words 'num lock' printed on the key.
Hold down the fn key and press the 'num lk' key. On some laptops this key is the same as the 'end' key.
Once the num lock function has been enabled, the Return key will function as an Enter key. If you want to use the Return key temporarily as an Enter key, you can simply hold down the fn key and press the Return key directly.
Note: In some cases you may need to turn off the fn key. If this is the case, go to the keyboard settings for your machine and uncheck the option for Enable Function Key or FN Key (The option might differ depending on your computer's manufacturer).