Solve Fraction Subtractions involving Mixed Numbers

In this activity, we will be subtracting fractions involving a mixture of improper fractions and mixed numbers.

 

To do most subtraction calculations with fractions, we need to have them all as improper fractions to start with.

 

Can you remember how to convert a mixed number into an improper fraction?

 

 

Here's a quick recap!

 

Say we have the mixed number 4 2/9

We convert this into an improper fraction by multiplying the whole number (4) by the denominator (9) and then add on the numerator (2)

4 x 9 = 36 

36 + 2 = 38

4 2/9 = 38/9

 

Once we have got both our fractions as improper ones, we can do the calculation.

 

If we end up with an improper fraction at the end of the calculation, we will need to convert it back to a mixed number.

 

For example, say we get 17/5 as an answer.

To convert it into a mixed number, we divide the numerator by the denominator.

17 ÷ 5 = 3 remainder 2 (this is 3 whole numbers and 2 fifths left over)

We write this as 3  2/5

17/5 = 3  2/5

 

 

Let's try an example.

 

Example

Complete the fraction equation.

3 2/5 - 4/5

 

Step 1: Convert the mixed number into an improper fraction: 3 2/5 = 17/5

 

Step 2: Do the subtraction: 17/5 - 4/5 = 13/5

 

Step 3: Convert the answer back into a mixed number: 13/5 = 2 and 3/5

 

It might look complicated but just take it one step at a time. You can look back at this introduction at any point by clicking on the red help button on the screen.

 

 

Are you ready to have a go at some questions now?