1.2 Adding & Subtracting Integers

In this lesson, we use real-world contexts like money, debt, temperature, and elevation to make sense of adding and subtracting positive and negative numbers.

Learning Targets

  • Add and subtract positive and negative integers
  • Use context to explain what an answer means
  • Record key information and show clear mathematical thinking

Key Vocabulary

  • Integer — A positive or negative whole number, including zero
  • Positive — A value greater than zero (gain, increase, above)
  • Negative — A value less than zero (loss, debt, below)

Lesson Flow

Get Started

  • KenKen puzzles using addition and subtraction (positive numbers only)
  • Focus on reasoning and numeracy to warm up your brain

Activity

  • Work through projected Integer Reasoning Tasks with your group
  • Tasks use real-world situations such as money, temperature, and elevation

Practice

  • Independent practice using Green, Blue, and Black questions
  • Choose challenges that push your thinking while staying accurate

Wrap Up

  • Reflect on which context helped you understand integers the most

Green • Blue • Black Practice

Practice questions are grouped into Green, Blue, and Black levels. These levels are about challenge, not speed.

  • Green — Core skills everyone is expected to complete
  • Blue — Shows proficiency through deeper reasoning
  • Black — Extends your thinking beyond proficiency

Start with Green, move to Blue, and try Black when you are ready. As the semester goes on, Blue and Black questions will become more challenging.

How We Take Notes in Math 8

Many problems in class are projected instead of printed. Your notes should show what matters and how you are thinking.

  • Key information (starting value, changes, important numbers)
  • Your work (math, diagrams, number lines, or words)
  • The final answer explained in context

If the problem is on the screen, the important information should appear in your notes.

Resources

Use solutions to check your understanding — not to copy answers.

Next Up

In Lesson 1.3, we will extend this thinking to multiplying and dividing integers and look for patterns that explain why the rules work.