4. (6 points) The calculation result of the expression $2015 \frac{1999}{2015} \times \frac{1}{4}-\frac{2011}{2015}$ is $\qquad$ .
$$
\begin{array}{l}
\text { [Solution] Solution: } 2015 \frac{1999}{2015} \times \frac{1}{4}-\frac{2011}{2015} \\
=\left(2015+1-\frac{16}{2015}\right) \times \frac{1}{4}-\left(1-\frac{4}{2015}\right) \\
=(2015+1) \times \frac{1}{4}-\frac{16}{2015} \times \frac{1}{4}-1+\frac{4}{2015} \\
=504-\frac{4}{2015}-1+\frac{4}{2015} \\
=504-1+\frac{4}{2015}-\frac{4}{2015} \\
=503+0 \\
=503
\end{array}
$$

Therefore, the answer is: 503
$$