[thaumasiotes]

> though if you need to preserve decimal results, you need approximation logic for division, since dividing two rationals with denominators that are powers of 10 may result in a rational with a denominator that is not a power of 10.

This is also true for adding, subtracting, and multiplying, though in those cases it is always trivial to convert the result into a form where the denominator is a power of 10.