Because 3^2 = 9 When you do (⅓)^2 what you are really doing is (1^2)/(3^2) = 1/9
If you have (⅔)^2 you do (2^2)/(3^2) = 4/9
Fractions get smaller because the denominator is also being squared which makes the denominator get bigger and when the denominator is bigger, you are dividing by a larger number which gives you a smaller answer. Whereas when you raise a whole number to an exponent, only the numerator get bigger because the denominator is 1 and 1 raised to any exponent is still 1
