Adding & Subtracting Integers CSI Mystery Worksheets

Inside the case file

Halloween adding and subtracting integers for middle school, grade 6, grade 7, grade 8 and grade 9, in a CSI Mystery Detective case where the zombie outbreak started at school. Positive and negative numbers identify the culprit: how fast it moves, how much it smells and how many brains it gets through come down to integers, and one zombie outside used to be someone your students knew. Math worksheets print in color or black and white with answer keys; October needs only a stapler. Students carry a running total along a path, color the correct arrow, decode secret messages from their answers and rule out suspects until one description fits and the mystery ends.

The Case: Run Zombies Run

The outbreak started at school. Friends, family and teachers have all gone the same way, and the survivors have barricaded themselves into what is left of the building. One of the zombies outside used to be someone your students knew. Working out which one means working the integers - how fast it moves, how much it smells, how many brains it gets through - until only one description fits.

What's Inside

• Adding and subtracting integers along a path where the running total settles the clue
• Positive and negative number problems that color the correct arrow forward
• Decoding a secret message from integer answers
• Checking worked integer problems for errors and tallying the results
• A second decoding page built on adding and subtracting negative numbers
• Full color and black-and-white versions of every page
• Answer keys for the whole case

What Is a CSI Mystery Detective Case?

Students are the detectives and math is the only evidence they are handed. That is the whole of a CSI Mystery Detective case: work the page, rule a suspect out with every correct answer, close the case on the last name standing. It runs as a math escape room with no locks, no app and no prep. It is also self-marking in practice, which ordinary math worksheets are not - a wrong answer produces a culprit who cannot exist. Use it as a math activity, in math centers, or as a sub plan.

When to Use This Resource

• Integer review before or after a unit test
• Halloween week in October, when a normal worksheet will not hold them
• Math centers, early finishers and independent work
• Emergency sub plans that run themselves
• End of year review, when attention is thin and the work still has to happen

Grade Levels

Built for grade 6 and grade 7, and it holds up for grade 8 and grade 9 students who need integer review. Sixth graders meeting negative numbers for the first time usually work it in pairs; older students run it independently and finish inside a lesson.

Why Teachers Love CSI Mystery Detective Cases

• Zero prep - print and hand out
• Self-checking by design, because a wrong sign breaks the deduction
• A middle school activity that is not babyish
• Works as a whole lesson, a center, or a filler for an awkward afternoon

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