Evaluate each expression below without a calculator. 

1. $27^{1/3}$ 

   Hint (a):

   $27^{1/3} = \sqrt[3]{27}$ 

2. $16^{1/4}$ 

   Hint (b):

   $16^{1/4} = \sqrt[4]{16}$ 

3. $49^{1/2}$ 

4. $1000^{1/3}$