Answer
The fractions of outcomes which is less than $5$ is $\frac{2}{3}$.
Work Step by Step
We know that the sample space of equally likely outcomes is $ S=\left\{ 1,2,3,4,5,6 \right\}$.
There are six outcomes in the sample space, so $ n\left( S \right)=6$.
The event of getting a number less than 5 can be represented by $ E=\left\{ 1,2,3,4 \right\}$.
There are four outcomes in this event, so $ n\left( E \right)=4$.
Therefore, the probability of rolling a number less than 5 is:
$\begin{align}
& P\left( E \right)=\frac{n\left( E \right)}{n\left( S \right)} \\
& =\frac{4}{6}
\end{align}$
Thus, the fraction of outcome which is less than $5$ is $\frac{2}{3}$.
