Perimeter (Customary & Metric)
Mystery Detective Worksheets · Grades 3–5 · Printable Detective Pack
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Inside the case file
Perimeter worksheets for 2nd grade, 3rd grade and 4th grade, set out as five printable Mystery Detective math cases in customary and metric units. Completely no prep math activities for math centers, morning work, early finishers, homework and sub plans, print and go with answer keys for every page. One download holds the five cases in inches and feet, the same five again in centimeters and meters, a full black and white set, and a color in page for whoever finishes first.
Perimeter lands in the middle of the geometry unit, and this is the set to hand out once the rule is taught and a class simply needs the reps. A correct measurement knocks a clue out, so the page tells a student how they are doing before it tells you. Having both measurement systems in the one file means the same five cases work whichever units your curriculum uses.
The Cases
- Mystery Chocolates - who left the box
- Showing Mindfulness - a secret kind deed
- Missing Shapes - the teacher's shapes vanish
- 2D and 3D Shape Songs - a singer nobody saw
- Missing Library Book - the book never came back
What's Inside
- Five color case pages, twelve shapes to measure on each
- The same five cases again in centimeters and meters
- Every case a second time in black and white
- An answer key for every case, both unit sets
- A color in page for early finishers
- A teacher instruction page, print and go with nothing to prepare
- Triangles, squares, rectangles and irregular shapes throughout
What Is a CSI Mini Mystery Detective?
One printed page holding one crime and the clue list that solves it. Each clue carries a measurement, the twelve shapes on the page produce those measurements, and a correct perimeter knocks a clue out. Work to the last shape and a single suspect is left standing. Get one wrong and nothing matches, which sends a student back over their working before you ever see it.
When to Use This Resource
Reach for this once perimeter has been taught and the class needs practice that holds their attention, and again later in the year when geometry needs keeping warm. It suits a whole class, a small group, or the two or three who have finished everything else, and the answer keys mean it marks itself. Because both measurement systems sit in the one download, it also covers a class that meets metric in one unit and customary in another. Use it for math centers, morning work, early finishers, homework, sub plans and homeschool lessons.
Grade Levels
Written for 2nd grade, 3rd grade and 4th grade. Fifth graders who still need perimeter firmed up get plenty out of it, and confident second graders manage it with a little support.
Why Teachers Love These Cases
- A correct perimeter matches a clue, so students check their own work
- Customary and metric versions are both in the download
- Color and black and white sets, however you like to print
- A color in page for whoever finishes first
- Five cases covers a week of geometry practice
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