This activity is an introduction to the multiplication of simple decimals.

Example

Complete the following multiplications.

We know that 31 x 8 = 248

What are: 

3.1 x 8  and 31 x 0.8

Answer

When a number in the question is divided by 10, we must also divide the answer by 10.

                                     

 

Answers are both 24.8

You can always check that you are right by counting the number of decimal places in the calculation and the answer. There should always be the same number of digits after the decimal point in the calculation as there are in the final answer.

Let's try some questions on this now.