Exponents are multiplying the number that has the exponent by itself how many number of times the exponent is. I worded this kinda weirdly, so here's an example. 2^4. 2 is the number that has the exponent, and 4 is the exponent. Now you would do 2x2x2x2. So 2^4 = 16. However if you use fractions, you are multiplying the fraction by itself how many number of times, making the fraction even smaller. So 1/2^4 would result in 1/2*1/2*1/2*1/2 or 1/16, which is smaller than 1/2.
