Multiplying Decimals

This lesson teaches how to multiply decimals by treating them as whole numbers initially, then placing the decimal point in the product based on the total number of decimal places in the factors. It includes an example of multiplying 8/10 by 7/10, resulting in 56/100, and another example with 12.4 and 3.6, resulting in 44.64. Estimation is used to predict the product, aiding in verifying the result. The lesson concludes with a summary of the traditional method for decimal multiplication.

What is the first step in multiplying two decimals?

• Add the decimals together.

• Multiply them as if they were whole numbers.

• Subtract the smaller decimal from the larger one.

• Divide the decimals by 10.

How do you determine where to place the decimal point in the product?

• Count the total number of digits to the right of the decimal points in the factors.

• Place it randomly in the product.

• Always place it after the first digit.

• Ignore the decimal point entirely.

What is a reasonable estimate for the product of 12.4 and 3.6?

• About 36

• About 48

• About 60

• About 72

What is the product of 36 times 124?

• 3724

• 4464

• 3600

• 1240

Where should the decimal point be placed in the product of 12.4 and 3.6?

• Between the 4 and 6

• After the first digit

• At the end of the number

• Before the first digit

How many digits should be to the right of the decimal point in the product of 12.4 and 3.6?

• Three digits

• Two digits

• Four digits

• One digit

What is the final product of multiplying 12.4 by 3.6?

• 48.00

• 44.64

• 50.24

• 36.00