Basic level

Order of operations

When several operations meet in one expression, we evaluate them in a fixed order: brackets first, then powers, then multiplication and division, and finally addition and subtraction. Learn the rules and practise them on examples.

Before you start

This topic builds on earlier ideas. Before you start, it's worth working through the lessons below — they'll make everything click:

All formulas

  • Multiplication before addition

    2+34=142 + 3 \cdot 4 = 14

    first 3 · 4 = 12, then 2 + 12

  • Brackets first

    (2+3)4=20(2 + 3) \cdot 4 = 20

    brackets change the order: first 2 + 3

  • Power before multiplication

    232=162^3 \cdot 2 = 16

    first 2³ = 8, then 8 · 2

  • Left to right

    2043=1320 - 4 - 3 = 13

    operations of the same rank are done left to right

When several different operations meet in one expression, the result depends on the order in which you carry them out. So that everyone gets the same answer, mathematics fixes one standard order.

The order-of-operations rule

Carry out operations in this order:

  1. brackets — whatever is inside first (from the innermost),
  2. powers and roots,
  3. multiplication and division,
  4. addition and subtraction.

Operations on the same level (multiplication and division together, or addition and subtraction together) are done left to right.

Why the order matters

Compare two expressions that differ only by a bracket:

2+34=14but(2+3)4=202 + 3 \cdot 4 = 14 \qquad \text{but} \qquad (2 + 3) \cdot 4 = 20

In the first, multiplication takes priority, so compute 34=123 \cdot 4 = 12, then 2+12=142 + 12 = 14. In the second, the bracket says add first: 2+3=52 + 3 = 5, then 54=205 \cdot 4 = 20.

Same level — left to right

Multiplication and division rank equally, so you don't "always multiply first" — you go from the left:

12:32=42=812 : 3 \cdot 2 = 4 \cdot 2 = 8

Had we multiplied 32=63 \cdot 2 = 6 first, we would get the wrong 12:6=212 : 6 = 2. The same goes for addition and subtraction: 2043=1320 - 4 - 3 = 13, working left to right.

Compute: 20 − 4 · 2 + 6 : 3.

Practice

Work through a set of exercises — they get harder as you go. At the end you'll see your score and the mistakes worth reviewing.

Exercise 1 of 6Score: 0
2 + 3 × 4 =

Common mistakes

  • Working left to right, ignoring priority2+342 + 3 \cdot 4 is 1414, not 2020.
  • "Multiplication always before division" — no: they rank equally, so go left to right.
  • Losing brackets — a bracket can change the result entirely, so copy it carefully.

Formula card

Topic: Order of operations

  • Multiplication before addition

    2+34=142 + 3 \cdot 4 = 14

    first 3 · 4 = 12, then 2 + 12

  • Brackets first

    (2+3)4=20(2 + 3) \cdot 4 = 20

    brackets change the order: first 2 + 3

  • Power before multiplication

    232=162^3 \cdot 2 = 16

    first 2³ = 8, then 8 · 2

  • Left to right

    2043=1320 - 4 - 3 = 13

    operations of the same rank are done left to right

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