When you are given any number to an exponent, you need to multiply it by itself as many times as the exponent's number. For example, if you got 4^7, you would multiply 4 * 4 * 4 * 4 * 4 * 4 *4 for a total of 7 times. In this case, it is 1/2 * 1/2 * 1/2 because the exponent is 3, meaning you do that 3 times.
