This is a free factors, multiples, primes and square numbers game for 4th and 5th grade: a five-minute detective case you put on the board and solve as a class. It practices 4.OA.B.4 (factor pairs, multiples, prime and composite). There are no logins, no student accounts and nothing to print unless you want the full case afterwards.
Why it works for factors, multiples, primes and square numbers
The clues are exactly the questions in the standard: is the badge a multiple of 6? Is it prime? How many factors does it have? Is it a square number? To clear a suspect the class has to test the badge, and testing six numbers against a clue is a lot more factor practice than it feels like.
How to run it
- Put it on the board. Tap Put it on the board above the case and it fills the screen. Six suspects, each wearing a badge number. One of them did it.
- Read clue 1 out loud. The class works out which badges the clue rules out. Tap each suspect it clears; a correct tap stamps them CLEARED, a wrong one just wobbles.
- Clues 2 and 3 unlock as you go. Keep clearing until one suspect is left, then tap them to close the case. The reveal explains every clue.
- Play it again. New lineup keeps the clues and shuffles the suspects. New clues gives you a fresh case. Round 2 and Round 3 are waiting in the tabs.
Three tips from the classroom
- Keep a hundreds chart on the board and circle the multiples as the class names them.
- When a clue says exactly 6 factors, list the factor pairs for one badge together before the class tries the others.
- Ask how do you know it is prime? every time. The answer should be a list of numbers that do not divide it.
Making it easier or harder
For a class new to factors, stay on multiples and odd and even by skipping clues you do not want yet (tap New clues for a fresh set). For a fast class, ban the hundreds chart.
Questions teachers ask
What numbers does it use?
Badges from 12 to 100. Clues cover multiples of 2 to 10, prime and composite, square numbers, how many factors a number has, and comparing.
Does it explain the answer?
Yes. When the last suspect is caught, the case shows why that badge fits all three clues, including the factor count or the square root.
Is there a printable version?
The packs below are the printable version on the same standard: a page of problems, a lineup of suspects, every right answer crosses one off. Answer keys included.
