Apply componendo on $\dfrac{3}{2} = \dfrac{6}{4}$ to get—

Componendo adds the denominator to the numerator: $\dfrac{3}{2}\to\dfrac{3+2}{2}=\dfrac{5}{2}$ and $\dfrac{6}{4}\to\dfrac{6+4}{4}=\dfrac{10}{4}$. Hence $\dfrac{5}{2}=\dfrac{10}{4}$.