Question

Is 5/12 bigger than 3/7

Answer 1

5/12 is not bigger than 3/7

Answer 2

You can figure out if two fractions are bigger by just cross multiplying the numerator and denominator of each fraction.  

$\frac{5}{12} \frac{3}{7}$

Multiply the 5 and 7, and then the 3 and 12. Be sure to start with the numerator of the first fraction. 
$\frac{5}{12} \frac{3}{7}$
5 * 7 = 35, 3 * 12 = 36
So $\frac{3}{7}$ is bigger.