Convert mixed number to fraction.
$$\color{blue}{ 3 } ~ \dfrac{ 0 }{ \color{red}{ 4 } } = \frac{ \color{red}{ 4 } \cdot \color{blue}{ 3 } + 0 }{ \color{red}{ 4 } } = \frac{ 12 }{ 4 }$$ .Simplify $ \dfrac{ 12 }{ 4 } $ by dividing both 12 and 4 by their GCD, which is 4. GCD(12, 4) = 4.
$$ \frac{ 12 }{ 4 } = \frac{ 12 : \color{blue}{ 4 } }{ 4 : \color{blue}{ 4 } } = \frac{ 3 }{ 1 } $$