I would find a common factor between the numerator and the denominator.
Numerator:
1 and 3
Denominator:
1 and 36
2 and 18
3 and 12 <--
4 and 9
3 in the lowest comment multiple
[tex] \frac{3}{36} [/tex]
3/3 = 1
36/3 = 12
So, the answer is [tex] \frac{1}{12} [/tex]