Do I need an account? No. SolveOn creates a random username for you. Deleting the app deletes your local progress; use Settings → Delete my data to remove server data.
Why did my Skill Rating go down? Skill Rating estimates demonstrated ability from Ranked Runs; it can rise or fall. Practice never changes it.
What level is the math? The library runs from Grade 9 through university on one rating ladder: number sense and algebra, quadratics and trigonometry, functions and sequences, advanced functions and calculus, contest problems in the style of high school math competitions, and first- and second-year university topics.
What is free? Everything competitive — Ranked Runs, the Weekly Contest, leaderboards — and unlimited practice by course, topic or difficulty. SolveOn+ adds topic analytics, targeted training, history review, rating over time, contest-style sets and worked solutions.
How do I cancel SolveOn+? Subscriptions are managed by Apple: iPhone Settings → your name → Subscriptions → SolveOn+. Deleting the app or your SolveOn data does not cancel a subscription.
An answer was marked wrong but I think it's right. Enter exact values (fractions like 3/4, or π/6, √2/2). Decimals are accepted only for terminating values or when the question says to round. Tell us the question topic and we'll check it.