Convert mixed number to fraction.
$$\dfrac{ -15 }{ 40 }$$ .Simplify $ \dfrac{ -15 }{ 40 } $ by dividing both -15 and 40 by their GCD, which is 5. GCD(-15, 40) = 5.
$$ \frac{ 15 }{ 40 } = \frac{ 15 : \color{blue}{ 5 } }{ 40 : \color{blue}{ 5 } } = \frac{ -3 }{ 8 } $$