If you want to type the ² of x² or (a+b)² 

Hold down the Alt key while typing 253 or 0178 on the keypad 
at the far right of your keyboard with Num Lock on (lit up).  It 
won't work with the number keys above the letter keys.  You 
must use the keypad at the far right of your keypad.  
You can also type x³ by holding Alt down while typing 0179 on the
keypad.  You can also get x⁴ x⁵ x⁶ x⁷ x⁸ x⁹ 
by typing &# followed by the numbers plus a semicolon

8308; 8309; 8310; 8311; 8312; 8313;.  

Edwin