If there are no significant digits to the left of the decimal point, then you will end up with a proper fraction.
Take the significant digits to the right of the decimal point -- That is the numerator of your fraction. For the denominator, write a 1 followed by a zero for every digit, significant or otherwise, to the left of the decimal point.
If there are significant digits to the left, then you have a mixed number. Treat the decimal part as above and just put the fraction you develop after the whole number part.
John
My calculator said it, I believe it, that settles it