Integers & Number Lines

Positive and negative numbers, ordering and operations

Explanation

What are Integers?

Integers are all whole numbers including negatives: … −3, −2, −1, 0, 1, 2, 3 …

On a number line, numbers increase as you move right and decrease as you move left.

Ordering Integers

Larger numbers are always to the right on a number line.

Example: Order −5, 3, −1, 0, −8 from smallest to largest:
→ −8, −5, −1, 0, 3

Adding and Subtracting Integers

  • Adding a positive number → move right on the number line
  • Adding a negative number → move left (same as subtracting)
  • Subtracting a negative number → same as adding a positive
    e.g. 5 − (−3) = 5 + 3 = 8

Multiplying and Dividing Integers

SignsResult
Positive × PositivePositive
Negative × NegativePositive
Positive × NegativeNegative
Negative × PositiveNegative

Rule: Same signs → positive result. Different signs → negative result.

Absolute Value & Key Tips

The absolute value of a number is its distance from zero (always positive).
|−7| = 7   |4| = 4

  • Temperature problems are a common real-world context for integers
  • Watch out for double negatives: − (−x) = +x
Practice Questions

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