Subtraction is the very case where relative error might matter most, and error relative to magnitude of the original unsubtracted numbers causes the most surpri

Subtraction is the very case where relative error might matter most, and error relative to magnitude of the original unsubtracted numbers causes the most surprises. Absolute error has useful applications, without any doubt, and regardless of arithmetic operation, but it probably doesn’t make sense to say it’s “better” without a specific problem in front of us, and without specific goals and priorities. Error tolerance is always up to the user.