Divide by 12 twice or once by 144. then take the LCM and you are left with 1,3 and 5. and then the numbers are a combination of multiplying one or both of the twelves into different combinations of these numbers..
(12) * (12*1*3*5)
(12*1)*(12*-3*5)
...
...
...
(brackets indicate the numbers)
+4 
