Math enthusiasts and riddle gurus are sure to love a mind-bending puzzle involving a king, a scale, and a counterfeit coin. Middle and high schoolers work through a video that describes a mathematician's challenge to find a false coin in a collection of 12 using only three chances at a balance scale.

Concepts

riddles, logic, balancing scale, problem solving strategies, problem solving techniques, deduction, deductive reasoning

Show More Show Less

Additional Tags

math

Show More Show Less

Instructional Ideas

• Assign the riddle in writing for homework before class the next day and see how many people solved it before presenting the video
• Include in a math class when discussing problem solving strategies, or in a science class in a lesson about mass and measurement

Classroom Considerations

• The riddle is quite tricky and likely requires more explaniation from the teacher
• Assessment questions focus on the specific way the narrator solved the problem in the video

Pros

• Paused section includes helpful reminders about the parameters of the riddle
• Extension section offers background information to the puzzle, as well as a way to simplify it if needed (reducing the coins to 9 instead of 12)

Cons

• None

Common Core

HSS-MD.B.5.a HSS-MD.B.7