Well, I'm not much of a mathmetician, but I think anybody could figure out that if you divide the second number by the first number, you come up with your "magic number" every time.

I searched around on the internet for "decimal to fraction conversion" and came across an interesting site that had a piece of java that does it on the fly. It starts out with the smallest fraction and gets increasingly more precise. Check it out.

Another site I found listed some common fractions that you can round to.

Anyways, if I were the company, I'd find a slightly better algorithm than that...