Correct. The number $\displaystyle\sqrt{{{2}}}\usepackage{cmbright}\Huge\$ is irrational because it cannot be represented as a fraction; it is a non-repeating and non-terminating decimal. 2 and $\displaystyle\frac{{1}}{{2}}\usepackage{cmbright}\Huge\$ are both rational numbers because they can be expressed as fractions.