Download ppt - CONFIDENTIAL1 “Multiplying Decimals By Decimals”

CONFIDENTIALCONFIDENTIALDecimal Decimal MultiplicationMultiplication

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WARM UPWARM UP

1)5.15 x 101)5.15 x 1055 = 515,000 = 515,000

2) 3.14 x 7 = 21.982) 3.14 x 7 = 21.98

3)0.007 x 6 = 0.0423)0.007 x 6 = 0.042

4)99.99 x 3 = 299.974)99.99 x 3 = 299.97


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Multiplying Decimals By DecimalsMultiplying Decimals By Decimals

When multiplying a decimal by a decimal, multiply as with whole numbers.

To place the decimal point, find the sum of the number of decimal places in each factor.

The product has the same number of decimal places.

Let’s begin today


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Multiplying DecimalsMultiplying Decimals

For example: Find 4.2 x 6.7For example: Find 4.2 x 6.7

4.24.2x 6.7x 6.7 294294

252252 28.1428.14

One decimal place

One decimal place

Two decimal places

The product is 28.14. Compared to the estimate, the product is reasonable.

Estimate 4.2 x 6.7 ->4x7 or 28


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Multiplying Decimals By DecimalsMultiplying Decimals By Decimals

Find 1.6 x 0.09 =Find 1.6 x 0.09 =

1.6

x0.09

0.144

One decimal place

Two decimal place

Three decimal place

Let’s practice

The product is 0.144. Compared to the estimate, the product is reasonable.

Estimate: 1.6 x 0.09= 2 x 0=0


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Multiplying DecimalsMultiplying Decimals

Your turn! Multiply 0.014 x 3.7Your turn! Multiply 0.014 x 3.7

0.014

x 3.7

0.0518


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Multiply:-

1) 5.7 x 2.8 =15.96 2) 4.12 x 0.07=0.2884

3) 0.12 x 5.3 =0.636

Practice Problems


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Tea BreakTea Break


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Try to solveTry to solve

http://www.thekidzpage.com/onlinejigsawpuzzles/kids-jigsaw-puzzles/12-piece-jigsaw/07-01-06-fworks3.html


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Let’s check what you understandLet’s check what you understand

Now, try to answer.Now, try to answer.

What is the number of decimal places in What is the number of decimal places in the product of 5.974 x 3.21 ?the product of 5.974 x 3.21 ?

The number of decimal places in the product is 5


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AssessmentAssessment

2) 0.7 x 2.5 =1.75

1) 1.5 x 0.7 =1.05

3) 0.8 x 2.4 =1.92

4) 9.4 x 0.7 =6.58

5) 0.8 x 0.4 =0.32

6) 0.24 x 0.4 =0.096


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AssessmentAssessment

9) 2.6b, if b=2.05

7) 1.4x, if x = 0.067 8) 0.04t, If t =3.2

10) 1.33c, if c =0.06

0.0938 0.128

5.33 0.0798


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Life Situation ProblemsLife Situation Problems11) Juan is buying a video game that 11) Juan is buying a video game that costs $32.99. The Sales Tax is found costs $32.99. The Sales Tax is found by multiplying the cost of the video by multiplying the cost of the video game by 0.06. What is the cost of the game by 0.06. What is the cost of the sales tax for the video game?sales tax for the video game?

Cost of the Sales tax for the video Cost of the Sales tax for the video game = $ 32.99 x 0.06 game = $ 32.99 x 0.06

= $ 1.9794 =$ 1.98= $ 1.9794 =$ 1.98


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Let’s recall what we studied todayLet’s recall what we studied today

When multiplying a decimal When multiplying a decimal by a decimal, multiply as with by a decimal, multiply as with whole numbers. To place the whole numbers. To place the decimal point, find the sum of decimal point, find the sum of the number of decimal places the number of decimal places in each factor. The product has in each factor. The product has the same number of decimal the same number of decimal places.places.


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Wow! We studied a lot.

That’s all for today

Bye.