Correct the Decimal Point

Teaching Notes

Focus: Multiplying Decimals by 1/10, 1/100, and 1/1000. Use the worked example and teaching sequence below to explain the reasoning before independent practice.

Before You Begin

• Understand decimal place value.

Teaching Steps for Parents and Teachers

1. Multiplying by 1/10 is equivalent to dividing by 10.
2. For 1/100 or 1/1,000, divide by 100 or 1,000.
3. Use zeros as needed to hold places and check that the result is smaller for a positive starting number.

Worked Examples

Calculate 3.47 × 1/100.

1. Multiplying by 1/100 is the same as dividing by 100.
2. Each digit has one hundredth of its previous value.
3. 3.47 ÷ 100 = 0.0347.

Answer: 0.0347

Common Mistakes and How to Help

Multiplying by 1/100 makes a positive number smaller; multiplying by 100 makes it larger.

Multiply 0.0347 by 100 to recover 3.47.

Questions to Check Understanding

• Should the product be larger or smaller than 3.47?
• How can multiplying by 100 check division by 100?

Practice Advice

Work through the example together. Ask the learner to explain the first two problems, then try three independently. Review the first incorrect step before assigning more practice.

Next Practice

• Use New Numbers to practice the same skill with different values.
• If the learner needs help, return to the example and model each step before trying again.