So, to work with negative exponents you need to multiply like a positive exponent, and move the decimal over double the digits place each time.
Examples:
If it is 4 with an exponent of -2, then you will multiply 4 by 4 to get 16, and then move the decimal over double the amount of digits. There are two digits, so you will move the decimal over four digits.
So the answer to 4 with an exponent of -2 would be .0016.
