Adding & Subtracting Integers CSI Mystery Worksheets | Grades 5–9 | Monster Mummy

October is when adding and subtracting integers gets its best hearing in middle school, and this CSI Mystery Detective case gives grades 6, 7, 8 and 9 an ancient Egypt tomb to work it in. Positive and negative numbers, subtracting integers and adding negative numbers fill the CSI math worksheets, with answer keys for every page and color and black-and-white versions ready to print. Something in the sealed tomb is awake, and only the integers on the walls can say what. Students carry a running total along a path, color the correct arrow forward and decode two secret messages, each answer removing a suspect until the mystery has a name.

The Case: The Monster Mummy

Your students are with an archaeological team that has found a sealed tomb and gone in anyway. In the first chamber there is a cup, glowing faintly, with two snakes for handles. Everything that has happened since started there. Something in this tomb is awake now, and the only way to say what it is - how tall, how fast, how bad it smells - is to work the integers on the walls.

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
• A matching page where the line drawn passes through the letter that matters
• 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?

Each page asks one question about the mummy and hands your students the integer problems that answer it. They solve, they eliminate, and the case closes when one suspect is left. Sign errors surface immediately, because a wrong sign breaks the message and the description stops making sense.

When to Use This Resource

• Integer review before or after a unit test
• An ancient Egypt topic, alongside your history and reading work
• 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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