Rewrite each expression below as an exponential expression with a base of 2.

1. 16 

   Hint (a):

   2 to ___ power = 16?

2. $\frac { 1 } { 8 }$ 

   Hint (b):

   $2^3=8$ and $2^{-1}=\frac{1}{2}$

3. $\sqrt { 2 }$ 

   Hint (c):

   Raise the base to a fractional power.

4. $\sqrt [ 3 ] { 4 }$ 

   Answer (d):

   $2^{\frac{2}{3}}$