find the common factors. Numbers that will go into both of these numbers evenly. You know that both numbers are even so you can write the problem like this
2*12
-------
2*14
you still have both 12 and 14 even so you take another 2 and write it like this
2*2*6
--------
2*2*7
7 is a prime number meaning it can only be divided by itself and 1 so it cannot be reduced any further. You can cancel everything that is the same on the top and bottom
6/7 is the reduced form.