### Adding and subtracting decimals

Adding and subtracting decimals is a similar process to the one used to add and subtract whole numbers. Understanding place value is most important to the process.

#### Adding decimals

If you were adding whole numbers, you might set out the calculation 453 + 136 in this way with the place values of each number lined up.

H | T | O | ||
---|---|---|---|---|

4 | 5 | 3 | ||

+ | 1 | 3 | 6 | |

= | 5 | 8 | 9 |

When the calculation involves adding the decimal numbers 453.741 and 136.157, you set out the working in a similar way, making sure that the place value parts and the decimal points are lined up.

H | T | O | . | tenths | hundredths | thousandths | |
---|---|---|---|---|---|---|---|

4 | 5 | 3 | . | 7 | 4 | 1 | |

+ | 1 | 3 | 6 | . | 1 | 5 | 7 |

= | 5 | 8 | 9 | . | 8 | 9 | 8 |