## How to add and subtract common fractions.

Goal:

## Theory:

Part 1

Download the free support file…We have created a Maths Helper Plus document containing the completed example from this topic. You can use this to practice the steps described below, and as a starting point for solving your own problems.

File name:‘Decimals to common fractions.alg’ File size: 3kbClick hereto download the file.If you choose` ‘Open this file from its current location’, then Maths Helper Plus

shouldopen the document immediately. If not, try the other option: ‘Save this file to disk’, then run Maths Helper Plus and choose the ‘Open’ command from the ‘File’ menu. Locate the saved file and open it.If you do not yet have Maths Helper Plus installed on your computer,click herefor instructions.

## Method:

Part 2

Use the place value of the last digit after the decimal point to write the decimal as a fraction.

For example, in the decimal fraction: **23.56**, the last digit, **6**, is in the hundredths place.

So the entire number can be expressed in hundredths as follows:

To demonstrate this procedure with more steps, enter the decimal number into Algematics as the sum of units, tenths, hundredths and so on, like this:

We will use this example in the steps below.

Use the (simplify) command to convert mixed numbers to improper fractions in their lowest terms.

Use the (common denominator) command to display the working for adding or subtracting two common fractions.

The steps below demonstrate how to add or subtract common fractions showing working, and also how to add or subtract mixed numbers.

##### Step 1 Enter the data

Click and type your expression into the maths box in the data entry dialog box.

If the ‘EMPTY’ message is not displayed between the blue buttons, click the button until the message: ‘INSERT’ appears.

**Use the ‘ * ’ symbol for multiply, and the ‘ / ’ symbol for divide.**

** Maths…**

23.56 = 23 + 5/10 + 6/100 |
---|

and then click

##### Step 2 Put over a common denominator

Click the (common denominator) button to put these terms over a common denominator, like this:

##### Step 3 Step 3 Simplify.

Click the (simplify) button several times until a single fraction is obtained. Clicking again will reduce the fraction to its lowest terms, if possible.

**23.56 ** simplifies to:

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