Square Simple Decimals

When we square a number that is less than 1, the answer is smaller than the original number.

 

 

Example

Work out (0.3)²

 

Answer

We must calculate 0.3 x 0.3

 

We know that 3 x 3 = 9

But now we must divide each of the 3s by 10

and therefore we must divide the 9 by 100.

 

9 ÷ 100 = 0.09

 

So,  0.3² = 0.09

 

Similarly,  0.7² = 0.49

 

and  0.03² = 0.0009

 

The easiest way to calculate these tricky problems is to count decimal places.

The rule is that you should always have the same number of decimal places in the answer as in the calculation.

 

So, in 0.3² we have 0.3 x 0.3 which has a total of two decimal places.

The answer of 0.09 also has two decimal places.

 

In 0.03² we have 0.03 x 0.03 which has four decimal places.

The answer of 0.0009 also has four decimal places.

 

Let's try some questions now - but don't forget to count those decimal places!