Math Mystery

In this Remarkable Idea, students will use various math skills to solve a crime.

This activity addresses:

  • Critical thinking
  • Math
  • Cause and effect
  • Alternative methods of access

What you need:

  • Cardboard box (for the safe)
  • Crime scene tape/crepe paper
  • Analog Clock (teaching clock, real clock, etc.)
  • Step-by-Step
  • iPad with SoundingBoard app
  • TalkingBrix
  • Calculator
  • Various crime scene things (anything that can be placed at the crime scene to throw off your detectives)


1. Create a secret code worksheet. How the message is coded is up to you, some options include (numerical codes, transportation codes, solve the equation codes, etc.). An example message would be: To: RR, The safe is in Mrs. Swenson’s classroom. Signed, PP. Students will use this information to narrow down their suspects.
2. Set the clock to 3:15.
3. Record times to the TalkingBrix for students to choose from.
4. Record the script to the Step-by-Step.
5. Print out or write on a white board the information of the 6 suspects. Students can cross off suspects that don’t fit the crime.
5. Create overlays using the AbleNet Symbol Overlay Maker app.

What to do:

The students will see the crime scene and must collect clues to solve the crime. Have a student activate the Step-by-Step to contact the police chief, he will give the detectives some information (you may wish to write down the 4 things he/she mentions to look for). As students progress through the activity, they will check in with him/her.

Secret Message
At the crime scene, there will be a crumpled up piece of paper with a message. For example: RR, The safe is in Mrs. Swenson’s class. PP
The students must solve this piece of the puzzle to get the initials of the person in the letter.

Broken Clock
At the crime scene, there will be a broken clock that reads 3:15. The time on this clock is important because it will help the security guard look at the right time on the security camera.
Students can use the TalkingBrix to choose the correct time from a field of three.
*Check in with the Police Chief with the time from the clock.*
When the security guard checks the tape, he will see that the suspect is 6’2”.

What was stolen?
Left over in the safe is $13.57. The safe originally had $160.00 in it, how much was stolen? Students can use calculators or the SoundingBoard app to answer.
*Check in with the Police Chief.*


“Alright detectives, we had a break in sometime last night. We don’t have a whole lot to go on. Look for clues and gather evidence. We are going to need a name, the time this happened, how tall the thief is, and how much money was stolen. I’ve faxed over a list of suspects to help you out. If you find out the time of the crime call me back, I will look over the security camera footage. Good luck.”
“So did you get a time?”
“Ok, just give me a minute here and I’ll see if the tape shows anything (pause) well I can’t see his face, but the suspect is 6’ 2” tall. I hope that helps. Remember we need to know who it was, and what they stole.”
“Have you solved the crime yet detectives?”
“Who was it and how much did they take?”
“Good work! Why don’t you head on home for the day and rest up.”

Character Suggestions:

  Creepy Craig Putrid Polly Queasy Quentin Revolting Ralph Rotten Roberta Stinky Stella
Height 5’4” 5’4” 6’2” 6’2” 5’6” 4’11”
Weight 209lbs 134lbs 161lbs 206lbs 149lbs 109lbs

Additional Suggestions:

Create full RAP sheets for the criminals. Cartoon mug shots can be found online.
To make this more challenging, add extra steps students will need to solve, such as give suspect height in centimeters on the RAP sheet instead of feet and inches, provide the key for the secret message somewhere else at the crime scene, etc.
This website will let you create a secret code worksheet:

This can be a whole group activity, or each student can work to solve the crime independently; however, the lesson must progress as a group.
Provide small notebooks for students to record clues.
Choose a student to be the crime scene photographer and take pictures of clues using an iPad, Blue2 Bluetooth switch, and the camera app.*