You could say that it is "three one twelfths," or 3 twelfths, which simplifies to 1/4.
Mathematically, you multiply the numerators and denominators together, so it would be
[tex] \frac{1}{12} * \frac{3}{1}
[/tex]
[tex] \frac{1*3}{12*1} [/tex]
[tex] \frac{3}{12} [/tex]
[tex] \frac{1}{4} [/tex]
