How to Multiply Decimal Numbers

​Tarah is trying to multiply 2 decimal numbers but does not know how. She wants to pull from what she knows to try and figure it out...

20 x 0.30 ​

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This is the expression she is trying to solve

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Multiple Choice

What is 20 x 30?

• 60

• 600

• 6000

• 160

She noticed that

0.30

can be broken down into smaller equations

30 x 0.01

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or 30 x 1/100

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0r 30 ÷​ 100

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Multiple Select

Rewrite the entire equation 20 x 0.30 using Tarah's logic (Choose all that apply)

• 20 x 30 $$\div\ 100$$  

• 20 x 30 x 100

• 30 x 100

• 20 $$\div$$  100 x 30

Open Ended

Why do both of the equations (20 x 0.30) and ( $$20\ \times30\ \div100$$  ) get you the same answer?

Tarah said he copied her idea!!! Why would she say that?

​*T&T

Moussa showed his work a different way

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Draw

Use Tarah and Moussa's strategy to solve the following: 0.91 x 15

Draw

What if both numbers are decimals? What strategy can we use? Show your work to solve 0.91 x 0.15

Multiple Select

What equation represents 0.91 x 0.15 ? [Select all that apply]

• 91 x 15 x 100

• 91 x 15 $$\div$$  100

• 91 x 15 $$\div$$   10000

• 91 x 15 $$\div\ 10^4$$  

Draw

The principal is building a new classroom. The length will be 8.9 feet and the width will be 10.1 feet. What will be the total area of the room?