Answer
$-4$
Work Step by Step
The top number is $\text{
positive
}$ and the bottom number is $\text{
negative
.}$ Since the signs of the numbers are different, subtract the numbers and copy the sign of the bigger number. Hence, \begin{array}{r}\require{cancel} 5 \\\underline{\phantom{} -9 }\\
-4
\end{array}