How to Multiply Decimals

Multiplying decimals is a process that’s similar to multiplying whole numbers but with an extra step of placing the decimal point in the product (the result of multiplication). Here’s a detailed explanation:

Ignore the Decimals at First:

When multiplying two decimal numbers, you initially ignore the decimals. Just multiply the numbers as if they were whole numbers.

Count the Decimal Places:

After multiplying, count the total number of decimal places in both of the original numbers.
For example, if one number has two decimal places and the other has one, the total number of decimal places is three.

Place the Decimal in the Product:

In your product (the result of your multiplication), count back from the rightmost digit the number of decimal places you counted in step 2. Place the decimal point there.
If your product doesn’t have enough digits to count back the total number of decimal places, add zeros to the left of your product until you can.

Let’s go through an example to illustrate this:

Suppose you are multiplying 3.4 (one decimal place) by 0.25 (two decimal places).

First, ignore the decimals and multiply 34 by 25. Then, since there are three decimal places in total (one from 3.4 and two from 0.25), you will place the decimal in the product so that there are three digits after it.

Let’s calculate this as an example.

In the example, multiplying 3.4 by 0.25 gives a product of 0.85. Here’s the breakdown of the process:

Multiply as if they are whole numbers: 34 × 25 = 850
Count the total number of decimal places in the original numbers: 3.4 has one decimal place, and 0.25 has two, so the total is three.
Place the decimal point in the product to have three digits after it. Since 850 as a whole number doesn’t have three digits after a decimal, we read it as 0.850, which simplifies to 0.85.

Therefore, 3.4 × 0.25 = 0.85.