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Grade 7 · Math · Unit 3 of 20

Add & Subtract Integers

Positives, negatives and zero pairs

What your child practises

Adding and subtracting positive and negative numbers with number lines, temperatures and elevations, including the idea that subtracting a number is the same as adding its opposite.

Ontario Curriculum expectation: B2.4 · adding and subtracting integers

How we explain it

Children can open this short lesson before they practise.

  1. On a number line, adding moves right and subtracting moves left.
  2. A positive and a negative of the same size cancel out: +1 and −1 make 0.
  3. Subtracting a negative is the same as adding a positive.

Example: −3 + 5 = ? Start at −3 on the number line. Move 5 to the right: −2, −1, 0, 1, 2. Answer: 2

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Put these integers in order from least to greatest.

    • 4
    • 10
    • -14
    • -8
    • -11
    Show answer

    -14 → -11 → -8 → 4 → 10

    Hint: Picture a number line: the farther left, the less. Every negative is less than zero, and a negative farther from zero is less, so -14 < -11. The least here is -14.

  2. Question 2

    A hiker is 60 m above sea level. A scuba diver is 6 m below sea level. How far apart are they, measured straight up and down?

    answer boxm

    Show answer

    66 m

    Hint: Write them as integers: 60 and -6. The difference is 60 − (-6) = 60 + 6 = 66 m.

  3. Question 3

    What is -15 − (-19)?

    -15 − (-19) = ?

    answer box

    Show answer

    4

    Hint: Subtracting is the same as adding the opposite: -15 − (-19) = -15 + 19 = 4.

  4. Question 4

    Start at -5 and add (-9). Where do you land?

    -15-10-505?
    • 4
    • -14
    • -15
    • 14
    Show answer

    -14

    Hint: Adding a negative number moves left. From -5, jump 9 to the left to land on -14.

  5. Question 5

    Which expression has the same value as -9 − (-5)?

    • -5 − (-9)
    • -9 + 5
    • -9 + (-5)
    • 9 + (-5)
    Show answer

    -9 + 5

    Hint: Subtracting a number is the same as adding its opposite. The opposite of -5 is 5, so -9 − (-5) = -9 + 5 = -4.

  6. Question 6

    Amir is scuba diving at -14 m (below the surface). Amir swims up 11 m, then down 2 m. What integer gives Amir's new position?

    answer boxm

    Show answer

    -5 m

    Hint: Up is + and down is −: -14 + 11 − 2 = -5. Work left to right.

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