Adding & Subtracting Integers

Inside the case file

Adding and subtracting integers worksheets for 6th grade and 7th grade: five Mystery Detective integer math cases with positive and negative numbers throughout. No prep, print and go, full answer keys, for math centers, warm ups, early finishers, homework, test prep and sub plans. Adding and subtracting integers practice for 6th grade and 7th grade, positive and negative numbers throughout, with stories written for middle school. It works as a math center, a warm up, test prep or a sub plan through the integers unit, and every CSI Mini Mystery Detective page is self-marking.

Getting the signs right is the whole skill with integers, and a stolen phone and a hacked account get a middle school class looking twice at every one of them. The marking is student-led, so the signs get checked on the page. Five Mystery Detective math cases from one download cover the last week of the unit.

The stories are written with older students in mind: a social media bully, a kidnapped teacher and a careless burglar are three of the five. Students add and subtract integers, then cross off the clue that matches each answer. A sign error gives a number that isn't on the list, and students notice that themselves.

The Cases

1. Box of Chocolates - an unsigned gift on the desk
2. The Stolen Phone - a phone taken from a friend
3. Social Media Bully - finding who runs the account
4. The Kidnapper - where the teacher has been taken
5. Bungling Burglar - a break-in at a friend's house

What's Inside

• Five integer cases, color
• The five cases again in black and white
• An answer key for every case
• Addition and subtraction with positive and negative numbers
• Teacher instructions

What Is a CSI Mini Mystery Detective?

A CSI Mini Mystery Detective is a printed case with the problems and the clue lists on the same page. Each clue has a number. When an answer matches, that clue is out. Whatever is left at the end is the solution: who, where and when.

When to Use This Resource

This set fits the second half of the integers unit, once students have used a number line and are ready to work without one. It also works as a refresher before integers show up in equations. Try it in a math center, with a small group, for test prep or on a sub day.

Grade Levels

Written for 6th grade and 7th grade. 6th graders use it at the end of the integers unit, and 7th graders use it for review.

Why Teachers Love These Cases

• Stories that suit middle school
• Color and black and white versions
• No prep at all
• Students can check their signs as they go

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