I refuse to believe you all would really let your players bully you into running only d&d
(ttrpg.network)
People complain about it a lot, but I've never actually ran into a system that uses any maths beyond what a five-year-old should be capable of. Closest I think might be Mutants and Masterminds with stacking multipliers, but still just some extra steps. Nothing that knowing your times tables wouldn't prepare you for.