You start with the successor function, which is the mathematical way of saying you have a button that adds one. Addition unlocks multiplication, multiplication unlocks exponentiation, and the upgrade tree keeps climbing the hyperoperations until the numbers stop having names. Sequences, primes and orbits arrive as separate systems on their own tabs.
Prestige goes Axiom, Theorem, Conjecture, Paradox, Transcendence, and each layer rewrites what the layer under it was for. The presentation is monospace and deliberately austere, with no art at all, which suits a game whose subject is notation. Offline production is in the settings and it is on by default.