Find three rational numbers between

$\frac{1}{4}$ and $\frac{1}{5}$

$\frac{1}{4}=\frac{1}{4} \times \frac{20}{20}=\frac{20}{80}$ and $\frac{1}{5}=\frac{1}{5} \times \frac{16}{16}=\frac{16}{80}$

Now, $\sqrt{2} \times \sqrt{3} \frac{18}{80}\left(=\frac{9}{40}\right), \frac{19}{80}$ are three rational numbers lying between $\frac{1}{4}$ and $\frac{1}{5}$.