What system, be it ttrpg, boardgame, videogame, whatever, has the most extreme math in terms of complexity as a baseline in your experience?
And not in like hyperspecific scenarios like magic the gathering but in a "yeah thats normal" way.
I'm going to construe "baseline complexity" to mean the sort of thing you'd reasonably expect to come up in any context where the game's mechanics come into play, which excludes stuff like, e.g., Silhouette CORE expecting you to derive cube roots during character creation, or Shadowrun 3rd Edition's "chunky salsa" rule for calculating area-of-effect damage in enclosed spaces – i.e., we're speaking strictly about the kind of math that at least potentially comes into play every single time you pick up the dice.
With that qualifier in mind, DC Heroes (1985) is probably a decent contender. In brief, all character traits are descriptively exponential (e.g., a stat of 2 is twice as good as a stat of 1; a stat of 3 is twice as good as a stat of 2; and so forth) – and unlike most games that just say their stats scale in this way, DC Heroes actually wants to preserve the logarithmic probability curve this conceit implies. However, since it came out in 1985, companion apps on mobile devices weren't yet a thing, and scientific calculators were still expensive pieces of specialty hardware, so rather than obliging players to break out a slide rule every time they pick up the dice, it uses dice rolls to produce linear column offsets on precalculated lookup tables. @annarcana did a reasonably comprehensive writeup on one of my recent threads, here:
https://www.tumblr.com/prokopetz/805968964301799424
