Add and Subtract using Standard Form

Using standard form is incredibly useful when we need to use either very large or very small numbers.

 

Areas we may use standard form include physics, biology and chemistry - from measuring the distance between planets to the mass of atoms.

 

 

In this activity, we will be adding and subtracting numbers written in standard form.

To be able to do this we need to be able to convert between standard form and ordinary form.

 

Example 1

5.1 x 10² as an ordinary number is 510

0.003214 written in standard form is 3.214 x 10^-3

 

Example 2 

Work out 

2.4 x 10⁴ + 3.6 x 10² 

 

To work out the answer to this question, we need to convert the numbers from standard form to ordinary form first.

 

2.4 x 10⁴ + 3.6 x 10² 

= 24,000 + 360

= 24,360

 

We can now change back to standard form.

 

2.4360 x 10⁴

 

Remember that for a number to be in standard form the base number needs to be between 1 and 10.

 

Example 3

Work out

2.4 x 10⁴ - 3.6 x 10³ 

 

First, let's convert the numbers from standard form to ordinary form first.

 

2.4 x 10⁴ - 3.6 x 10³ 

= 24,000 - 3,600

= 20,400

= 2.04 x 10⁴

 

Are you ready to jump in to the activity?