Wrong on purpose. Right by design.
Your kid stops taking answers on trust. Errol is the math companion who's always wrong : find his bad step, explain why it breaks, earn detective rank. It's the one skill AI can't hand them.
A movie starts at 3:45 and lasts 90 minutes. When does it end?
Five steps. One detective. One sneaky robot.
Every challenge follows the same beat. Errol works the problem out loud, your kid watches for slip-ups, then breaks down what went wrong in their own words.
Errol solves it
Step-by-step working, but one step is sneakily wrong.
Kid scans
Reads each step like a case file. No timer. No pressure.
Tap the slip
Highlight the bad step. Confidence drops on Errol's face.
Write the why
Explain what Errol got confused about, in their own words.
The reveal
Errol reacts. Real solution shown side by side. Rank up.
In a world flooded with AI, the rare skill is knowing when it's lying.
Most learning apps reward the right answer. We reward the right question . Because your kid will hear a hundred plausible answers a day, from chatbots, classmates, and confident strangers. Spotting the broken one is the superpower.
1 Calibrated wrongness Errors come in three tiers (Obvious, Sneaky, Expert) matched to age and skill. The sneakier the catch, the bigger the rank-up.
2 Always show the work Every solution Errol attempts is shown step-by-step. Kids learn pattern-matching for bad reasoning, not just bad answers.
3 Explain in their own words Submitting the catch isn't enough. Kids type a short explanation: the act that builds real understanding.
4 No grades. No leaderboard unless you switch it on. Just rank. Rookie → Inspector → Detective → Sherlock. Earned by catches, not speed.
Made for the homework table. Not the algorithm.
One Errol. Many moods.
Errol's confidence drops in real time. When your kid catches him, his face crumples. When they miss, he beams. Emotion is the hook.
The case file system
Every solve becomes evidence. Past catches are replayable, annotatable, and shareable: proof your kid is building a real skill.
No ads. No data harvesting.
We don't sell to your kid. We don't profile your kid. One subscription, no dark patterns, COPPA-respecting from day one.
Free for three cases a day. Honest from there.
Three cases a day, free. New accounts get the Parent plan free for 7 days, no card needed. Cancel anytime.
Save 50% the first year: only 50 founding family spots
Half price on yearly for the first 50 families. Lock it in before the seats are gone.
Free
· Not included: No parent dashboard
Learner
· Not included: No parent insights
Parent
Family
Siblings' progress side by side
Schools : flat-rate licensing for classrooms of 10+. Contact us →
Things parents actually ask.
Everything parents want to know before getting started.
Want to go deeper?
Practical articles for parents on raising kids who think critically about AI: error-detection learning, AI literacy, and the daily habits that build sharper minds.
Every kid can think critically
In a world full of AI-generated answers, the most important skill is knowing when the AI is wrong. Start building that skill today.