How to build a mental maths Reddit game with Claude
SphinxWar used Claude to build a Reddit mental maths game. Players keep a running addition total in their heads and use coloured digit feedback to solve a hidden number before their rows run out.
reddit.com
Suggested prompt
Suggested prompt written by Agents In Use, not the source author. Replace bracketed inputs and review tool permissions first.
Help build a small [platform] mental maths game. Give players a starting number and rows of additions, but keep the running total hidden. Use yellow feedback for digits present in [hidden answer] and green for correct positions. Limit attempts to [rows]. Explain ambiguous rules, provide a testable implementation and list checks I should perform before publishing. Do not claim educational benefits without evidence.
Reach people exploring AI agents
See placements →Evidence at a glance
Sourced account- Source poster / publisher
- u/SphinxWar
- Original account
- Read the source ↗
- Published
- Source link checked
- Reported result
- The author shared a playable game link and reports daily game posts plus custom games with three to ten columns and one to eight rows. The source does not establish learning benefits or document the exact Claude coding session.
- Human involvement
- The author describes the rules, shares the game and clarifies its behaviour in comments. The source does not document code review, testing coverage or the exact division of implementation work.
A linked account supports attribution. It does not mean we independently reproduced its result.
Report an issue with this case
Open correction emailOpens your email app with the case link included. Nothing is sent automatically.
How the agent did it
- The author had Claude build a mental maths game with Wordle-like digit feedback.
- The game combines hidden running addition totals, coloured clues and a limited number of attempts.
- The author shared a playable Reddit link, explained the rules and answered questions about custom games.
Reddit author SphinxWar reports using Claude to build a small mental maths game, then shares a link where people can play it. The idea borrows Wordle's coloured feedback, but players must also remember an addition total that the interface does not display.
Players begin with a starting number and add the numbers in successive rows. Each row builds on the previous total. A digit that appears in the hidden number turns a cell yellow. A digit in its correct column turns the cell green and solves that column. Players must solve every column before their rows run out.
In a follow-up comment, the author says the game posts daily on its subreddit. People can also create custom games with three to ten columns and one to eight rows. The hidden answer visible in the shared screenshot belongs to a finished, failed attempt, not the normal playing view.
The post describes Reddit's Devvit registration, local testing and installation route as guidance for other builders. It does not document the exact coding session, Claude interface or model, so those details remain unknown. The result is an author-reported game with a playable link, not an independently tested measure of learning or difficulty. It suits hobby developers exploring a small, rule-based game with AI coding help.
Prompt
Suggested prompt (written by Agents In Use, not the author's)
Source: Reddit · u/SphinxWar
Frequently asked questions
How does the game differ from Wordle?
Players must remember a running addition total. Digits in that total produce yellow or green clues about a hidden answer, and players have a limited number of rows.
Did the author identify the Claude model or coding interface?
No. The source credits Claude with building the game but does not specify Claude Code, a model version or a detailed coding transcript.
More details
About this account
Claude performed substantive game-building work according to the author. The post does not identify its interface, tool calls, model or how much code it produced without further prompting. The game's arithmetic and colour rules are deterministic, distinct from the AI's development role.
Firsthand account by u/SphinxWar: https://www.reddit.com/r/ClaudeAI/comments/1x8ndaa/i_had_claude_build_a_very_simple_mental_math_game/. Full public RSS post and returned comments captured on 19 October 2026. Body eligibility passed at 0.9. Outcomes are author-reported, not independently reproduced. Suggested prompt by Agents In Use, not the author's original prompt.
Credit: u/SphinxWar on Reddit
Source published
Added to Agents In Use
Source checked
Tools and topics
Claude · Reddit · Devvit
mental maths · Reddit games · hobby development
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.