Answer
12
Work Step by Step
In order to rewrite $\frac{3}{16}$ with a denominator of 64, we must first divide 64 by the original denominator.
$64\div16=4$
Therefore, we must multiply the original numerator by 4.
$\frac{3}{16}=\frac{3\times4}{64}=\frac{12}{64}$