GradeMap

Grade 8 · Math · Unit 4 of 11

Fraction Operations

Add, subtract, multiply and divide

What your child practises

Adding and subtracting fractions with unlike denominators, multiplying and dividing fractions, switching between mixed numbers and improper fractions, and finding a fraction of an amount.

Saskatchewan Curriculum outcome: N8.4 · multiplying and dividing fractions and mixed numbers

How we explain it

Children can open this short lesson before they practise.

  1. To add or subtract, use a common denominator.
  2. To multiply, multiply the tops and multiply the bottoms.
  3. To divide, flip the second fraction and multiply.

Example: 2/3 ÷ 4/5 = ? Flip the second fraction: 5/4. 2/3 × 5/4 = 10/12. Simplify: 5/6. Answer: 5/6

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

    Add: 3/4 + 2/6. Type the answer as a fraction in lowest terms.

    answer box

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    13/12

    Hint: Use a common denominator of 12: 9/12 + 4/12 = 13/12. Lowest terms: 13/12.

  2. Question 2

    Subtract: 6/10 − 3/6. Type the answer in lowest terms.

    answer box

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    1/10

    Hint: Common denominator 30: 18/30 − 15/30 = 3/30, which is 1/10 in lowest terms.

  3. Question 3

    Multiply: 2/6 × 1/4. Type the answer in lowest terms.

    answer box

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    1/12

    Hint: Multiply the numerators and the denominators: 2 × 1 = 2 and 6 × 4 = 24. 2/24 simplifies to 1/12.

  4. Question 4

    Divide: 2/3 ÷ 2/5. Type the answer in lowest terms.

    answer box

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    5/3

    Hint: Dividing by a fraction means multiplying by its reciprocal: 2/3 × 5/2 = 10/6, which is 5/3.

  5. Question 5

    Write 3 5/8 as an improper fraction.

    • 29/9
    • 29/8
    • 8/8
    • 30/8
    • 15/8
    Show answer

    29/8

    Hint: Multiply the whole number by the denominator and add the numerator: 3 × 8 + 5 = 29. Keep the denominator 8.

  6. Question 6

    1 4/6 + 4 1/3 = ?

    • 7
    • 5 5/9
    • 6
    • 5 5/6
    • 6 1/6
    Show answer

    6

    Hint: Add the whole numbers (1 + 4) and the fractions (4/6 + 1/3, using a denominator of 6), then carry if the fraction part is 1 or more. Total: 6.