10/5 Multiplication Lesson

10/5 Multiplication Lesson

I will calculate the product of a number and 10 or 100 by applying strategies and be able to explain the steps.

Open Ended

Warm-Up: Unit 1 Most Missed Question

A bag of snack mix weighs 8 and 9/100 ounces. What decimal is equivalent to 8 and 9/100?

Concept: Multiplying by 10s and 100s

Strategy # 1: Quick way

• When we multiply by 10, the product is the number with 1 zero to the right.

• When we multiply by 100, the product is the number with 2 zeroes to the right.

• This strategy ONLY works when multiplying by 10, 100, 1,000.......you are only attaching the zeroes at the end.

Open Ended

44 x 100 = ?

Open Ended

675 x 10 = ?

Open Ended

83 times 10 = ?

Open Ended

99 times 100 = ?

Open Ended

26 x 11 = ?

Strategy # 2: The Formal Way

• When multiplying numbers such as 324 and 10, a student is expected to use the properties of operations and place value. (Expanded Notation)

• Multiplying 324 by 10 means that each value from 324 is being multiplied by 10, so 324 x 10 = (300 + 20 + 4) x 10 = (300 x 10) + (20 x 10) + (4 x 10) = 3,000 + 200 + 40 = 3,240

For example, you see 324 x 10

• You are going to work it out using the Formal strategy (expanded notation) on your paper.

• Then, you will write your answer here.

• Ex. (300 + 20 + 4) x 10 = (300 x 10) + (20 x 10) + (4 x 10) = 3000 + 200 + 40 = 3240

• *Click the Shift button and the number 9 or 0 to get the parenthesis*

Open Ended

346 x 10

Open Ended

163 x 100

Multiple Choice

Use the Quick Way!

• 394,500

• $39, 540

• $359, 400

• $34,590

Multiple Choice

Use the Formal way/Expression/Expanded Notation.

• (3000 x 10) + (400 X 10) + (50 x 10) + (9 x 10)

• (3000 X 100) + (900 x 100) + (50 X 100) + (4 x 100)

• (3000 x 100) + (500 X 100) + (90 x 100) + (4 x 100)

• (3000 x 10) + (900 x 10) + (50 x 10) + (4 x 10)

Multiple Choice

Use the Quick Way!

• 394,500

• $39, 540

• $359, 400

• 34,590

Multiple Choice

Use the Formal way/Expression/Expanded Notation.

• (3000 x 10) + (400 X 10) + (50 x 10) + (9 x 10)

• (3000 X 100) + (900 x 100) + (50 X 100) + (4 x 100)

• (3000 x 100) + (500 X 100) + (90 x 100) + (4 x 100)

• (3000 x 100) + (900 x 100) + (40 x 100) + (5 x 100)

Open Ended

Essential Question: When Multiplying by 10s and 100s, what strategies should you use?

Poll

How confident are you with multiplying by 10s and 100s?

• Very Confident

• Very Confused

• I just need more practice

Independent Practice Time!

• Go to google classroom, click classwork.

• Click the one that says Concept Practice

• Open the google slides and practice multiplying by 10s and 100s - Use your strategies

• If you finish, you can do 25 minutes of I-ready and take the AR quiz for the 100 hungry ants.