How to Multiply Decimals

Multiplying decimals is very much like multiplying whole numbers. If you can multiply whole numbers, you just need to add a couple more steps to multiply decimals. Here are the steps you can use. For example, let's multiply 4.25 X 3.2.

Instructions

1. Line up numbers to the right. Do not worry about lining up the decimal points.

2. Starting at the right, multiply the ones digit on the bottom, by each number of the top. So, multiply 2 X 425 which is 850.

3. Place a zero place holder in the second line in the ones column.

4. Multiply the tens number on the bottom by each number on top. In this case, you are multiplying 3 X 425, which is 1275. If your number is longer, continue by adding two zeros as a placeholder in the third line and then multiply the hundreds number by each number in the top row. Continue until you have no more numbers in your bottom row to multiply.

5. Add the rows of number to get your answer, which is 13600

6. Count the number of digits after the decimal point. Count both the top and bottom numbers individually. In this case you have 2 numbers after the decimal point on top and one number after the decimal point on the bottom. This means your answer needs to have three numbers after the decimal point. Your final answer is 13.600.

7. Ignore any zeros on the end after your decimal point. This means instead of 13.600, your answer is 13.6.

Tips & Warnings

• If you were multiplying single digit decimals such as .9 X .5, you would simply multiply the numbers in your head and then place your decimal point so that two numbers fall after it. Your answer would be .45.