Multiply Decimals by Whole Numbers

This activity is about multiplying a simple decimal number by a whole number.

 

Example

Find the product.

3.1 x 8 = ____

 

Answer

First we work out 31 x 8

 

 

Then we deal with the decimal point as follows.

 

 

The answer is 24.8

 

The easiest way to do these calculations is to start by removing the decimal point, do the calculation and then add it back in at the end.

 

There should always be the same number of decimal places in the calculation as there are in the answer. In the example above, there is one decimal place (3.1), so there must be one decimal place in the answer (24.8).

 

Does that make sense?

 

 

Let's try some questions now.