Same skill as question 3 — Money and time: cents, coins, clocks and elapsed time — new numbers, no hints, generated and marked by code. Check you can do a new one now; holding it a week later is a separate test, and the plan schedules that.
This demo stores nothing: no account, no cookie, and your answer is not kept. Registered children get this check on every miss, and their result is recorded next to the question it came from.