Everyone gets the same challenge

Three kinds of challenge

Estimate

Fermi-style questions, like "how many piano tuners are there in Chicago?". Nobody expects you to know the answer. The point is to break a big question into small steps you can reason about, and land on a sensible number. We score how close you got on a log scale, so being off by a factor of two is a good result.

Explain

Pick the clearest explanation of an idea, or find the gap in one that doesn't quite work. It's practice for thinking clearly, and for noticing when something sounds right but isn't.

Spot

Find the fallacy, bias or error in a short text. Every answer comes with a short explanation, so you learn the pattern, not just the result.

Why the same challenge for everyone?

Because thinking is more fun when it becomes a conversation. Share your card with a friend, compare how you reasoned, or challenge them to beat your estimate. It's social without a feed, followers or comments.

What we share, and what we never share

We never share your check-in, your mood or your journal. Only what you choose: your streak, your Bambú and your challenge answers.

Questions

Is the daily challenge free?

Yes. Everyone gets the daily challenge and the anonymous comparison, on the free plan too.

Does it change at midnight?

There is one challenge per language per day, based on your local date. A new one appears each morning wherever you are.

How does the comparison work?

Once enough people have answered, we show where your answer landed compared with everyone else, anonymously. Before that, we tell you honestly how your answer compares with the expected range, without inventing numbers.

Can people see my answer?

No. Nobody sees your answer unless you choose to share your card, and the card never shows the correct answer, your mood or your check-ins.

Does it make me smarter?

We don’t promise that. It’s practice: a small daily workout for reasoning and attention, the way a short walk is practice for your body.