Python has the "fractions" module which provides a more powerful abstraction: It's not restricted to denominators that are powers of 10. > I don't know their

Python has the "fractions" module which provides a more powerful abstraction: It's not restricted to denominators that are powers of 10. > I don't know their performance characteristics It's easy to make some good guesses. Since (I'm guessing) it's implemented with pairs of integers, adding probably uses a / b + c / d = (ad + bc) / (cd) which is 3 multiplications and an addition, and multiplication probably uses (a / b) (c / d) = (ac) / (bd) so only two multiplications. So it's a small constant factor times the cost of integer multiplication, plus a bit of overhead for the wrapper class. So my back-of-the-envelope guess is that the fractions module is less than 10x slower than the same operation with integers, or fast enough for just about anything you do in a beginner level class. These numbers will change significantly if fractions are automatically reduced by gcd of numerator and denominator; I'm not sure about this point.