Exponential explosion help needed please

Uh huh...

\begin{array}{ccl}
\frac{2^{30} - 2^{29}}{2}& =& \frac{2^{30}}{2} - \frac{2^{29}}{2} \\
&& \\
& = & 2^{29} - 2^{28}\\
&&\\
& = & 2^{28}(2 - 1)\\
&&\\
&= & 2^{28}\end{array}

If you need to simplify further, use your calculator. :)