Topic Review — Decimals

Review Questions

1. Multiply these decimals: Fluency

   1. 4.5 × 3
   2. 2.8 × 6
   3. 1.2 × 1.5
   4. 3.6 × 0.5
   5. 0.7 × 0.9
   6. 2.4 × 2.5

2. Divide these decimals: Fluency

   1. 8.4 ÷ 4
   2. 15.5 ÷ 5
   3. 3.6 ÷ 0.9
   4. 7.2 ÷ 0.4
   5. 6.0 ÷ 1.2
   6. 9.9 ÷ 3

3. Round each number: Fluency

   1. 3.746 to 2 decimal places
   2. 12.384 to 1 decimal place
   3. 0.0567 to 3 decimal places
   4. 9.995 to 2 decimal places

4. Multiply or divide by powers of ten: Fluency

   1. 34.7 × 100
   2. 5.06 ÷ 10
   3. 0.08 × 1000
   4. 7.2 × 10²
   5. 630 ÷ 10³
   6. 0.045 × 10&sup4;

5. Which is the better buy? Show your working. Understanding

   1. Cereal A: 500 g for $4.20, or Cereal B: 750 g for $5.85
   2. Shampoo X: 300 mL for $6.90, or Shampoo Y: 500 mL for $11.00

6. Mia earns $24.60 per hour. Problem Solving

   1. She works 6.5 hours on Saturday. How much does she earn?
   2. She works 4.75 hours on Sunday. How much does she earn?
   3. What is her total weekend earnings?
   4. She spends $38.47. How much does she have left?

7. Add and subtract decimals: Fluency

   1. 12.6 + 8.45
   2. 30.0 − 14.73
   3. 5.8 + 3.25 + 0.7
   4. 100 − 63.48

8. Estimate first, then calculate: Understanding

   1. Estimate 3.8 × 4.2, then calculate.
   2. Estimate 19.6 ÷ 4, then calculate.
   3. A student says 2.3 × 1.5 = 34.5. Without calculating, explain why this answer is clearly wrong.

9. A 1.5 kg block of cheese costs $12.60. Understanding

   1. What is the cost per 100 g?
   2. How much would 400 g cost?
   3. A second cheese costs $3.80 per 200 g. Which is better value?

10. Order from smallest to largest: Fluency

    1. 0.45, 0.405, 0.54, 0.504
    2. 1.06, 1.6, 1.006, 1.066