Multiplying Decimals

To multiply decimals, ignore the decimal points and just multiply the numbers. Then count the total number of decimal digits (the digits to the
right of the decimal point) in the numbers you're multiplying. Count off that number of digits in your answer beginning at the right side and put the decimal point to the left of those digits.

Problem: 215.7 × 2.4

1. Multiply 2157 times 24: 2157× 24 86284314 51768
2. Because there are a total of 2 decimal digits in 215.7 and 2.4, count off 2 places from the right in 51768, placing the decimal point to the
left of the last 2 digits: 517.68

If your answer doesn't have enough digits, tack zeroes on to the left of the answer.

Problem: .03 × .006
1. Multiply 3 times 6: 3 × 6 = 18
2. You need 5 decimal digits in your answer, so tack on 3 zeroes: 00018
3. Put the decimal point at the front of the number (which is 5 digits in from the right):
.00018

Practice: You can practice multiplying decimals with these:
1. .05 × .6
2. .053 × 6.4
3. 38.1 × .0184
4. Joe earns $14.50 per hour. Last week he worked 37.5 hours. How much money did he earn that week?
5. Nuts cost $3.50 per pound. Approximately how much will 4.25 pounds of nuts cost? a. $12.25 b. $12.50 c. $12.88 d. $14.50 e. $14.88