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:
- AdditionAddition combines two or more numbers into one — the sum. Learn the names of the parts, the laws of addition (commutativity, associativity, identity element) and how to add in columns with carrying.
- SubtractionSubtraction is the inverse of addition — take the subtrahend away from the minuend to get the difference. Learn the names, the properties, the link to addition and how to subtract in columns with borrowing.
- MultiplicationMultiplication is repeated addition of the same number. Learn the names of the factors and the product, the laws of multiplication (commutativity, associativity, distributivity), the times tables and column multiplication.
- DivisionDivision is the inverse of multiplication — divide the dividend by the divisor to get the quotient. Learn the names, the link to multiplication, division with a remainder and why you must never divide by zero.
All formulas
Multiplication before addition
first 3 · 4 = 12, then 2 + 12
Brackets first
brackets change the order: first 2 + 3
Power before multiplication
first 2³ = 8, then 8 · 2
Left to right
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:
- brackets — whatever is inside first (from the innermost),
- powers and roots,
- multiplication and division,
- 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:
In the first, multiplication takes priority, so compute , then . In the second, the bracket says add first: , then .
Same level — left to right
Multiplication and division rank equally, so you don't "always multiply first" — you go from the left:
Had we multiplied first, we would get the wrong . The same goes for addition and subtraction: , working left to right.
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.
Common mistakes
- Working left to right, ignoring priority — is , not .
- "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
first 3 · 4 = 12, then 2 + 12
Brackets first
brackets change the order: first 2 + 3
Power before multiplication
first 2³ = 8, then 8 · 2
Left to right
operations of the same rank are done left to right
