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Multiply By 10s and 100s!

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Lesson Plan

Multiply By 10s and 100s!

Students will be able to determine products of a number and 10 or 100 using place value understandings.

Understanding how to quickly multiply by 10 and 100 makes mental math easier and builds a strong foundation for more complex multiplication and division problems.

Audience

4th Grade Students

Time

15 minutes

Approach

Interactive slides and quick practice.

Materials

Multiply By 10s and 100s! Slide Deck, and Quick Check Cool Down

Prep

Review Materials

5 minutes

Step 1

Introduction: The Power of Place Value (3 minutes)

3 minutes

  • Display the first slide of the Multiply By 10s and 100s! Slide Deck.
    - Engage students by asking: "What happens when we multiply a number by 10? How about by 100?" Allow for a few quick responses.
    - Explain that today we'll explore a 'superpower' that helps us multiply by 10 and 100 really fast: place value.

Step 2

Exploring Multiplication by 10 (5 minutes)

5 minutes

  • Move to the slides focusing on multiplying by 10.
    - Guide students through examples, emphasizing how each digit shifts one place value to the left, and a zero is added to the ones place.
    - Use visual cues on the slides to illustrate this shift. Ask students to verbalize the rule in their own words after a few examples.

Step 3

Exploring Multiplication by 100 (5 minutes)

5 minutes

  • Transition to the slides on multiplying by 100.
    - Explain that multiplying by 100 is like multiplying by 10, twice! Each digit shifts two place values to the left, and two zeros are added.
    - Work through examples, ensuring students see the pattern and understand why two zeros are added.

Step 4

Quick Check & Wrap-Up (2 minutes)

2 minutes

  • Present the Quick Check Cool Down to assess student understanding.
    - Review answers as a class and address any misconceptions.
    - Conclude by reiterating the importance of understanding place value in multiplication by 10 and 100.
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Slide Deck

The Power of Place Value!

How can we multiply by 10 or 100... SUPER FAST?

Welcome students and introduce the topic of multiplying by 10 and 100. Ask a quick engaging question.

Multiplying by 10!

When we multiply a number by 10, each digit moves one place value to the LEFT. We add a zero to the ones place!

Example: 3 x 10 = ?

Think: 3 tens = 30

Try it! 7 x 10 = ?


52 x 10 = ?


Explain what happens when we multiply by 10 using an example. Emphasize the digit shift and adding a zero.

Multiplying by 100!

When we multiply a number by 100, each digit moves two place values to the LEFT. We add two zeros to the ones and tens place!

Think of it as multiplying by 10, then multiplying by 10 again!

Example: 4 x 100 = ?

Think: 4 hundreds = 400

Try it! 6 x 100 = ?


85 x 100 = ?


Explain what happens when we multiply by 100 using an example. Emphasize the digit shift and adding two zeros. Relate it back to multiplying by 10 twice.

Quick Check!

What is...

  1. 9 x 10 = ?


    2. 15 x 10 = ?


    3. 2 x 100 = ?


    4. 34 x 100 = ?


Provide a quick check for understanding. Ask students to solve a few problems independently or with a partner.

Great Job!

Remember:

  • Multiply by 10: Shift digits one place left, add one zero.
  • Multiply by 100: Shift digits two places left, add two zeros.

Keep practicing your place value superpower!

Review the answers to the quick check and summarize the main takeaway. Encourage students to continue practicing.

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Cool Down

Quick Check: Multiply By 10s and 100s!

Instructions: Answer the questions below to show what you've learned about multiplying by 10 and 100.

  1. What happens to the digits of a number when you multiply it by 10?



  2. What happens to the digits of a number when you multiply it by 100?



  3. Solve: 7 x 10 = ?


  4. Solve: 25 x 10 = ?


  5. Solve: 4 x 100 = ?


  6. Solve: 63 x 100 = ?


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Answer Key

Quick Check: Multiply By 10s and 100s! Answer Key

Instructions: Review the answers and explanations below.

  1. What happens to the digits of a number when you multiply it by 10?

    Explanation: When you multiply a number by 10, each digit shifts one place value to the left, and a zero is added to the ones place.

  2. What happens to the digits of a number when you multiply it by 100?

    Explanation: When you multiply a number by 100, each digit shifts two place values to the left, and two zeros are added to the ones and tens place.

  3. Solve: 7 x 10 = ?

    Answer: 70
    Explanation: The digit 7 moves one place to the left from the ones place to the tens place, and a 0 is added in the ones place.

  4. Solve: 25 x 10 = ?

    Answer: 250
    Explanation: The digits 2 and 5 both move one place to the left. The 2 moves from the tens to the hundreds place, and the 5 moves from the ones to the tens place. A 0 is added in the ones place.

  5. Solve: 4 x 100 = ?

    Answer: 400
    Explanation: The digit 4 moves two places to the left from the ones place to the hundreds place, and two 0s are added in the ones and tens places.

  6. Solve: 63 x 100 = ?

    Answer: 6300
    Explanation: The digits 6 and 3 both move two places to the left. The 6 moves from the tens to the thousands place, and the 3 moves from the ones to the hundreds place. Two 0s are added in the ones and tens places.

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