An exponent is a numbers that is multiplied by itself by as many times as the exponent says so (ex: 2^2=2x2=4). If you took a fraction and raised it to the second power (aka squared it) you would have to multiply the exponent by itself. For example if you were to square one half ((1\2)^2=1\2x1\2) you would first multiply the numerators of the fractions (1*1=1) next you would multiply the denominators (2x2=4). In the end you cannot simplify the fraction and you get 1\4.