If you want to add up or subtract decimal fractions you can use the same techniques used to add up or subtract integers.

You only need to pay attention to the **position of the decimal mark**.

## Addition of decimal fractions

There are multiple methods to add up decimal fractions. You can either

- write the figures underneath each other and use written addition,
- or convert them into regular fractions and add them up this way.

### Procedure

$$6.256+2.73\\$$

Write the figures underneath each other so that the **decimal marks are directly beneath each other**.
If the figures contain a different amount of decimal places you need to **fill up the shorter number with zeros** until they both have the same number of decimal places.

%%\begin{array}{l} \hphantom{ +\; } 6.256\\ +\;2.730\\ \\ \end{array}%%

Add up the numbers without paying attention to the decimal marks. Then place the decimal mark of the solution directly underneath the others.

%%\begin{array}{l} \hphantom{ +\; } 6.256\\ \underline{+\;2.730}\\ \hphantom{ +\; }8.986 \end{array}%%

## Subtraction of decimal fractions

As with the addition of decimal fractions, there are two different approaches you can use. You can either

- write them underneath each other and use written subtraction
- or convert them to regular fractions and subtract them.

### Procedure

%%6.623-4.71\\%%

Write the figures underneath each other so that the **decimal marks are directly beneath each other**.
If the figures contain a different amount of decimal places you need to **fill up the shorter number with zeros** until they both have the same number of decimal places.

%%\begin{array}{l} \hphantom{ -\; } 6.623\\ -\;4.710\\ \\ \end{array}%%

Use written subtraction without paying attention to the decimal marks. Then place the decimal mark of the solution directly underneath the others.

%%\begin{array}{l} \hphantom{ -\; } \overset{5}{\not6}.\overset{16}{\not6}\;2\;3\\ \underline{-\;\;4.\;7\;1\;0}\\ \hphantom{-\;}\;1.\;9\;1\;3 \\ \end{array}%%