## Precalculus (6th Edition) Blitzer

The probability of getting a number less than five on a rolled dice is $\frac{2}{3}$.
We know that there are six outcomes on a dice i.e.$\left( \text{S} \right)\text{ = }\left\{ 1,2,3,4,5,6 \right\}$, so $\text{n}\left( \text{S} \right)=\text{ 6}$. And the event of getting a number less than $5$ can be represented by $\left( \text{E} \right)\text{ }=\text{ }\left\{ 1,2,3,4 \right\}$ So, there are four outcomes in this event, $\text{n}\left( \text{E} \right)=\text{ 4}$. Thus, the probability of getting a number less than $5$ is $\text{P}\left( \text{E} \right)\text{ = }\frac{\text{n}\left( \text{E} \right)}{\text{n}\left( \text{S} \right)}\text{ = }\frac{4}{6}\text{ = }\frac{2}{3}$.