Order of operations

The order of operations is a mathematical and algebraic set of rules. It is used to evaluate (solve) and simplify expressions and equations. The order of operations is the order that different mathematical operations are done. The standard mathematical operations are addition (+), subtraction (−), multiplication (* or ×), division (/), brackets (which are grouping symbols, like parentheses () or []) and exponentiation (^n or ⁿ, also called orders or indices).

Mathematicians have agreed on a correct order to use operations, and it is very important that they know these rules. When people are solving a problem with more than one operation, they will need to know the correct order to solve the problem correctly. Otherwise the answer will be wrong.

Rules

Follow all the rules in this order from left to right in the equation.

Brackets and indices

Use operations inside brackets and solve any indices. You should always solve brackets first when solving an equation.

Example:

(2 + 3) * (4 -1) + 2³

(2 + 3) * (4 -1) + 2³

5 * (4 -1) + 2³

5 * (4 -1) + 2³

5 * 3 + 2³

5 * 3 + 8

Multiplication and division

Solve any multiplication and division in the problem. Note that multiplication does not precede division, this is a common mistake while the fact is that they are solved from left to right as they occur.

Example:

5 * 4 - 9 / 3

5 * 4 - 9 / 3

20 - 9 / 3

20 - 9 / 3

20 - 3

Addition and subtraction

Lastly, solve any addition or subtraction.

Example of all rules

(1 + 8) * (4 - 1) + 16 / 2³

(1 + 8) * (4 - 1) + 16 / 2³

9 * (4 - 1) + 16 / 2³

9 * 3 + 16 / 2³

9 * 3 + 16 / 8

9 * 3 + 16 / 8

27 + 16 / 8

27 + 2

29

Ways to remember it

Please Excuse My Dear Aunt Sally

A good way to remember the order of operations is by remembering this phrase. The first letter of each word is also the first letter of a rule in the order.

Please: Parentheses (or brackets)

Excuse: Exponents (or indices)

My: Multiplication

Dear: Division

Aunt: Addition

Sally: Subtraction

BIDMAS/BODMAS

Another good way of remembering the order of operations is the word BIDMAS, or BODMAS. The letters of the word are the same as the first letter for each rule.

B stands for Brackets

I stands for Indices, O stands for Orders

D stands for Division

M stands for Multiplication

A stands for Addition

S stands for Subtraction