, I know (and I said before) that the Rat type should be used for rational numbers, but would not help for irrational numbers. In whatever base, irrational numbers will be approximations. However, there are many many computer applications that would benefit from accuracy in simple additions or subtractions of rational numbers. For example most applications dealing with monetary amounts. So the Rat type doesn't solve all issues, I agree with that and never made any claim to the opposite, but it would solve many issues.