What you do in World Challenge
One challenge a day: the same 50 questions for every player in the world. Answer as many as you can, as fast as you can. Your score puts right answers first and speed second, then you see where you rank on today's global board.
- Every question is the same for everyone, so the board is fair.
- Each answer is checked straight away. After three wrong tries, the question is skipped.
- A new set arrives at midnight UK time, and the board starts again.
- Everyone gets one run a day; with Pro you can play again.
Try it: 10 seconds
No pressure. Just see how it feels.
36 ÷ 4 = ?
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9
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Doc explains
Here's a secret: every quiz is a sneaky study session! When you pull an answer out of your memory, it tends to stay there longer than if you had simply read it again. Scientists call it the testing effect. And today the whole planet is pulling out the very same 50 answers, which I find rather thrilling.
The science idea
The testing effect: pulling an answer out of your memory helps you remember it better than reading it again.
It is also called retrieval practice. In the classic experiments, people who tested themselves on what they had read remembered more of it days later than people who studied it again.1 A meta-analysis found that practice tests helped learning more than restudying and every other comparison it looked at.2
World Challenge also has a leaderboard, and competition is a different topic with its own research, which is more mixed. Both are below.
What the research found
In two experiments, college students who took recall tests on a passage remembered more of it 2 days and 1 week later than students who studied it again, even though restudying made them feel more confident. After only 5 minutes, restudying was ahead.1
A meta-analysis found that practice tests were more helpful for learning than restudying and every other comparison condition, with the size of the benefit depending on how the tests were set up and who took them.2
Leaderboards are a different story. A meta-analysis of gamification in learning found small positive effects on learning, motivation and behaviour. For effects on behaviour, competition worked best when combined with collaboration, and the motivation and behaviour effects were less stable in the most rigorous studies.3
And competition on its own? A meta-analysis found no noteworthy overall link between competition and performance. Competing tends to spark two goals that pull in opposite directions: trying to beat others, which helps, and trying not to do worse than others, which gets in the way.4
How World Challenge uses it
- Every question asks you to pull the answer from memory and type it, with no options to pick from: the kind of retrieval the testing effect is about.2
- Right answers count first and time second, so a careful answer beats a rushed guess.
- After three wrong tries a question is skipped, so one hard sum never stalls the whole round.
- Everyone gets the same 50 questions, so the board compares like with like. It is there for fun: the research on competition is mixed.4
What this does and doesn’t mean
It does mean
It doesn’t mean
- The testing effect studies mostly used passages, word lists and facts checked days later. A mixed arithmetic quiz is closer to skill practice, so this is the same principle, not proof about sums.
- The classic experiments gave no feedback, while World Challenge tells you at once whether you were right: a different condition.1
- It does not mean competing makes you better at math: on average, competition did not improve performance.4
- The studies below tested their own tasks with their own volunteers. They did not test Math Workout.
References
Written in APA 7 style. Tap a number in the text to jump here, and the arrow to jump back.
- 1
Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249-255. https://doi.org/10.1111/j.1467-9280.2006.01693.x
- 2
Adesope, O. O., Trevisan, D. A., & Sundararajan, N. (2017). Rethinking the use of tests: A meta-analysis of practice testing. Review of Educational Research, 87(3), 659-701. https://doi.org/10.3102/0034654316689306
- 3
Sailer, M., & Homner, L. (2020). The gamification of learning: A meta-analysis. Educational Psychology Review, 32(1), 77-112. https://doi.org/10.1007/s10648-019-09498-w
- 4
Murayama, K., & Elliot, A. J. (2012). The competition-performance relation: A meta-analytic review and test of the opposing processes model of competition and performance. Psychological Bulletin, 138(6), 1035-1070. https://doi.org/10.1037/a0028324
Science last checked: 2026-11-05
