I believe Android's built-in calculator app takes this approach: https://dl.acm.org/doi/pdf/10.1145/2911981 https://dl.acm.org/doi/pdf/10.1145/2911981 It also

I believe Android's built-in calculator app takes this approach: https://dl.acm.org/doi/pdf/10.1145/2911981 https://dl.acm.org/doi/pdf/10.1145/2911981 It also uses rational numbers and arbitrarily large integer arithmetic.