Answer
$\frac{4}{7}$
Work Step by Step
$\frac{12}{7} \div $ 3
Change division to multiplication. Invert $\frac{3}{1}$ and write its reciprocal.
$\frac{12}{7}$ * $\frac{1}{3}$ = $\frac{12*1}{7*3}$ = $\frac{12}{21}$
Since 3 is the greatest common factor of 12 and 21, divide numerator and denominator by 3
So, $\frac{4*3}{7*3}$ = $\frac{4}{7}$