Multiply Decimals: Tenths x Tenths

Open Ended

How was your weekend?

Multiply Decimals: Tenths x Tenths

by Isabel Aguado

​Warm up

​Xtra Math (1 session)

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​Please make sure to complete the entire session before logging off!

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​You will owe recess for incomplete sessions.

​Vocabulary

Decimal - a decimal number can be defined as a number whose whole number part and the fractional part is separated by a decimal point.

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​Decimal Grid - Used to visually represent decimals as an area model.

​We will use grids today to represent tenths x tenths.

​How to Multiply Tenths x Tenths

​1. Represent one factor vertically (up and down).

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​2. Represent the other factor horizontally (left to right).

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​3. Your product is the area where both factors crossed each other.

Multiple Choice

What decimal number is represented in the image?

• 0.1

• 10

• 1

​0.1 or 0.10

​one tenth or ten hundredths is being represented vertically up and down in the image.

Multiple Choice

What decimal number is represented in the image?

• 30

• 0.3

• 3

​0.3 or 0.30

​three tenths or thirty hundredths is being represented in the image.

Multiple Choice

The image shows a visual representation of 0.1 x 0.3.  What is the product of 0.1  x 0.3?

• 0.03

• 0.30

• 3

0.03

​0.1 x 0.3 = 0.03

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​Three hundredths is the answer. If you count the units where both colors cross each other there are 3 out of 100 total units in the grid. Therefore, the answer is 0.03.

​Let's practice

​On your grid paper use the first grid to represent 0.2 x 0.2 and find the product. You may use two different colored pencils.

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​Click on the next slide to check your work.

​Let's practice

​On your grid paper use the first grid to represent 0.3 x 0.4 and find the product. You may use two different colored pencils.

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​Click on the next slide to check your work.

​Let's practice

​On your grid paper use the first grid to represent 0.8 x 0.3 and find the product. You may use two different colored pencils.

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​Click on the next slide to check your work.

Multiple Choice

What multiplication problem does the model represent?

• 0.6 x 0.3 = 0.18

• 0.3 x 0.2 = 0.06

• 3 x 2 = 6

Answer

​The model represents

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​0.3 x 0.2 = 0.06

Multiple Choice

Which model correctly represents 0.4 x 0.4 = 0.16 ?

Multiple Choice

Which model correctly represents 0.9 x 0.2 = 0.18 ?

Multiple Choice

The model represents 0.7 x 0.3 

What is the product?

• 10

• 0.10

• 0.21

• 21

Multiple Choice

On your grid paper, represent 0.4 x 0.7, select the correct model.

• model is not shown

Multiple Choice

On your grid paper, represent 0.5 x 0.4 what is the product?

• 0.24

• 0.20

• 0.020

• 0.024

Open Ended

How do area models help us when multiplying decimals?