Try doing some basic maths questions in the Lean Theorem Prover. Functions, real numbers, equivalence relations and groups. Click on README.md and then on "Open in CoCalc with one click".
License: APACHE
import data.rat.meta_defs run_cmd let q : ℚ := 3/15 in guard $ (reflect q : expr) = `((1/5 : ℚ)) constants (α : Type) (h : field α) attribute [instance] h run_cmd guard $ expr.eval_rat `(1/3 - 100/6 : α) = some (-49/3) run_cmd guard $ (expr.eval_rat ∘ rat.reflect) (-(5/3) : ℚ) = some (-5/3)