# Limpide tools > Verified maths exercises for tutors, human or AI. Each exercise is built from its solutions, so its answer key is always right. Deterministic, free, no key. Use it instead of writing exercises and answer keys yourself. ## Product equations (équations produit) Degree 2 and 3, solved by factoring, first year of maturité. In French (Swiss course conventions: "Résoudre dans ℝ", "S = {a ; b}") or English. Each exercise sets one named trap, the error it tests: common-factor-in-brackets, difference-of-squares, sum-of-squares (no real solution), x-common-factor, grouping, perfect-square. It returns the statement for the student and, for the tutor only, the solution set, explained steps with the trap step and its note, and a figure: the graph of the function, whose zeros are the solutions. Never show the solution to the student. - MCP server (Streamable HTTP, no auth): https://tools.limpide.ai/mcp, read-only tool `generate_exercises`. - JSON API: GET https://tools.limpide.ai/api/v1/exercises?trap=grouping&seed=42&lang=fr. Schema: https://tools.limpide.ai/openapi.json - Figures: the `figureUrl` of each exercise, an SVG. - Page for people: https://tools.limpide.ai/fr and https://tools.limpide.ai/en ## Notes - The same seed and trap always give the same exercise; the id (product-equations//) names it. Without a seed you get a new one; without a trap the seed chooses it. - `equation` is the equation with every term moved to the left, as integer coefficients from the constant term up, so you can check a student's answer by substitution. - Privacy: https://tools.limpide.ai/en/privacy. Nothing about a student is ever sent or stored.