# PSAT Math : How to multiply decimals

## Example Questions

### Example Question #1 : How To Multiply Decimals

45.728 x 3.2 = ?

Possible Answers:

1463.296

14632.96

14.63296

146329.6

146.3296

Correct answer:

146.3296

Explanation:

Multiply the numbers out in long format, then move the decimal point over the total number of decimal points in the two numbers (3 in the first, 1 in the second, so 4 total):

45.728 * 3.2 = 91456

91456 + 1371840 = 1,463,296 → 146.3296

Or just count the decimal points in the answer and make sure it's 4.

### Example Question #2 : How To Multiply Decimals

At the farmer's market, oranges are $0.30 each, apples are$0.25 each, bananas are $0.40 each, and tomatoes are$0.60 each. If Scott buys 3 oranges, 7 apples, 4 bananas, and 8 tomatoes, how much does he spend?

Possible Answers:

$11.40$9.05

$6.80$7.75

$10.40 Correct answer:$9.05

Explanation:

To find out how much Scott spends, we need to multiply the quantity of each fruit by its price and add them all up.

3 * $0.30 + 7 *$0.25 + 4 * $0.40 + 8 *$0.60 = $9.05 ### Example Question #3 : How To Multiply Decimals If is 25% of , what is the closest integer to the value of ? Possible Answers: Correct answer: Explanation: We can approximate the value of y pretty quickly: y ≈ 1(0.50)(52) = 26 Since y = 0.25x = (1/4)x we know that x = 4y ≈ 4(26) = 104 ### Example Question #1 : How To Multiply Decimals Possible Answers: 0.006 0.6 0.0006 6 0.06 Correct answer: 0.006 Explanation: It's much easier to work with whole numbers, so we'll ignore the decimals for the first step: 5 x 12 = 60 Now look at the decimals. To add them back in, think of 60 as 60.0. Now move the decimal point four places to the left: 0.5 x 0.012 = .0060 = .006 ### Example Question #5 : How To Multiply Decimals At the store, green fabric costs$4.53 a yard. How much does 3.8 yards of green fabric cost? (Round to two decimal places.)

Possible Answers:

$17.22$17.13

$17.12$17.31

$17.21 Correct answer:$17.21

Explanation:

This is a simple multiplication problem involving decimals. Simply multiply 4.53 by 3.8:

Now, round to the nearest two decimal places, giving an answer of 17.21.

### Example Question #2 : How To Multiply Decimals

Find the product. Round to the nearest hundredths place.

Possible Answers:

Correct answer:

Explanation:

The hundredths place is the position two places to the right of the decimal. Our product is . Rounding to the hundredths place results in .

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