The number $\displaystyle{1}\frac{{2}}{{3}}=\frac{{5}}{{3}}\usepackage{cmbright}\Huge\$ . Because it can be written as a ratio of two integers, it is a rational number. However, $\displaystyle{1}\frac{{2}}{{3}}\usepackage{cmbright}\Huge\$ is between 1 and 2 on the number line, so it cannot be a whole number.