# Order of operations: BIDMAS

## In a nutshell

The order of operations is a rule for which operation must be performed first. It is very helpful when having to solve questions involving multiple steps such as multiplication and subtraction.

## BIDMAS

BIDMAS is an acronym which identifies the order of operations.

#### Priority | #### Operation | #### Symbol/#### Example |

$1$ | **B**rackets | $()$ |

$2$ | **I**ndices | $2^2$ |

$3$ | **D**ivision | $\div$ |

**M**ultiplication | $\times$ |

$4$ | **A**ddition | $+$ |

**S**ubtraction | $-$ |

**Note: **If there is multiplication and division together in a question, the operation which comes first when reading from left to right is completed first. The same applies to addition and subtraction.

##### Example 1

*Calculate: *$30-3\times(8 -1).$

*Use **BIDMAS **to follow the order of operations and calculate the answer.*

* **B**rackets** **must be completed first:*

$8-1=7$

*The expression is now:*

$30-3\times7$

*There are no ***I**ndices, or **D**ivision** **so move onto **M**ultiplication:

$3\times7=21$

*The expression is now:*

$30-21$

*Finally, there is no **A**ddition** **so move onto **S**ubtraction:*

$30-21=9$

*Therefore,*

__$\underline{30-3\times(8-1)=9}$__