Multiplication and Estimation Techniques

The video tutorial explores different methods to compute 31.2 times 19. It begins by introducing the problem and encourages viewers to attempt solving it independently. The first method involves viewing 31.2 as 312 tenths and multiplying by 19, followed by converting the result back to a decimal. The video provides a detailed walkthrough of the multiplication process. The second method focuses on estimation, removing the decimal to compute 312 times 19, and then determining the decimal placement by estimating the product to be around 600. Both methods aim to verify the reasonableness of the result.

What is the first step suggested in the video to solve 31.2 times 19?

• Convert 31.2 into a fraction

• Estimate the result using round numbers

• View 31.2 as a number of tenths

• Directly multiply 31.2 by 19

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CCSS.2.NBT.A.3

How is 31.2 represented in the tenths method?

• As 3120 tenths

• As 3.12 tenths

• As 31 tenths

• As 312 tenths

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CCSS.6.NS.B.3

What is the product of 312 and 19 before converting back to a decimal?

• 592.08

• 59,280

• 592.8

• 5,928

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CCSS.3.OA.A.1

In the multiplication steps, what is the result of 3 times 9?

• 9

• 27

• 18

• 36

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CCSS.6.NS.B.3

What is the final decimal result of 31.2 times 19 using the tenths method?

• 0.5928

• 592.8

• 59.28

• 5,928

What is the purpose of using estimation in the video?

• To simplify the multiplication process

• To find an exact answer

• To verify the reasonableness of the result

• To avoid complex calculations

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CCSS.4.NBT.B.5

What approximate values are used for estimation in the video?

• 32 and 18

• 30 and 20

• 31 and 20

• 30 and 19

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CCSS.5.NBT.B.7

Where should the decimal be placed in the product to match the estimation?

• Before the first digit

• After the third digit

• After the first digit

• After the second digit

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CCSS.5.NBT.B.7

What is the estimated product of 31.2 and 19 using round numbers?

• 620

• 610

• 600

• 590

What is the key takeaway from using estimation in multiplication?

• It eliminates the need for calculations

• It is faster than actual multiplication

• It helps in checking the accuracy of the result

• It provides an exact answer