You can use Mathematica or Sage that can use any number of digits https://www.wolframalpha.com/input?i=FEDCBA987654321_16+%2F+123456789ABCDEF_16+-14 https://www

You can use Mathematica or Sage that can use any number of digits https://www.wolframalpha.com/input?i=FEDCBA987654321_16+%2F+123456789ABCDEF_16+-14 https://www.wolframalpha.com/input?i=FEDCBA987654321_16+%2F+... You can use special libraries for floating point that uses more mantisa. In most sciences, numbers are never integers anyway, so you have errors intervals in the numerator and denumerator and you get an error interval for the result.