For monetary values, though, the denominators should be the same. This means that the denominator won't get arbitrarily large. For serious uses of rationals y

For monetary values, though, the denominators should be the same. This means that the denominator won't get arbitrarily large. For serious uses of rationals you need to have control over when the top and bottom are divided by the GCD. For currency you want to keep the denominator at 100. 50/100 wants to remain as that and not get simplified to 1/2.