Whole Numbers & Operations · Grade 5
Order of Operations: Why 2 + 3 × 4 Is 14
Quick answer
Operations are carried out in a fixed order: parentheses first, then exponents, then multiplication and division left to right, then addition and subtraction left to right. So 2 + 3 × 4 is 14, not 20. The order is a convention, agreed so that one expression has one meaning, and parentheses exist to override it when a different order is wanted.
What you'll learn
- Carry out operations in the correct order
- Use parentheses to change the order
- Write an expression that records a calculation described in words
One expression, one meaning
What is ?
Working left to right gives . Multiplying first gives .
Both are reasonable readings, and that is the problem. An expression has to mean one thing, so mathematicians agreed on an order. The agreed answer is .
The order
| Step | Operation |
|---|---|
| 1 | parentheses |
| 2 | exponents |
| 3 | multiplication and division, left to right |
| 4 | addition and subtraction, left to right |
Steps 3 and 4 each cover two operations of equal rank. That is the part people get wrong, and it has its own section below.
Equal rank means left to right
Multiplication does not outrank division. They are the same step, done in the order they appear.
Left to right: the division comes first.
Doing the multiplication first would give , which is wrong.
The same holds for addition and subtraction:
Adding first would give . Left to right settles it.
Parentheses override the order
Parentheses say do this first, whatever the usual order would be.
Same numbers, same operations, different answers — because the parentheses changed which came first.
That is what parentheses are for. Without them there would be no way to write “add first, then multiply”, and the fixed order would be a restriction rather than a convention.
When parentheses are nested, work from the innermost outward:
Some writers use square brackets or braces for the outer layers — , , — purely so the pairs are easier to match by eye. They all mean the same thing.
Working through a long expression
Take one step at a time and rewrite the whole expression each time. The temptation is to do two things at once, and that is where errors come from.
Parentheses:
Exponents:
Multiplication and division, left to right:
Addition:
Why the order is what it is
The convention is not arbitrary, even though it is an agreement.
Multiplication is repeated addition, so it is a shorthand for a group of additions. In , the stands for — a single bundled quantity. Evaluating that bundle before adding it to the keeps the shorthand meaning what it stands for.
The same logic puts exponents above multiplication. has the standing for , one bundled quantity, so it resolves first.
Each level of the order is a shorthand for the level below it, and the shorthand is unpacked before the level below is applied.
Where this is used
Every calculator, spreadsheet and programming language follows this order. A
spreadsheet formula =2+3*4 returns , not , and so does every
programming language you are likely to meet.
It also underlies algebra. In , the is a single term precisely because multiplication binds tighter than addition. That reading is what makes and different expressions.
Worked examples
Common mistakes
Practice problems
-
Find .
Answer
Full solution
Multiplication first: , then .
-
Find .
Answer
Full solution
The parentheses first: .
-
Find .
Answer
Full solution
Left to right: .
-
Find .
Answer
Full solution
Left to right: .
-
Find .
Answer
Full solution
, then , then .
-
Find .
Answer
Full solution
The parentheses first: .
-
Write “subtract from , then multiply by ” as an expression.
Answer
Full solution
The subtraction must happen first, so it needs parentheses.
-
Find .
Hint
Innermost parentheses first.
Answer
Full solution
, then , then .
-
Find .
Answer
Full solution
Parentheses first: .
Then division: .
-
Working out , Leo does the multiplication first and gets . Find his error.
Hint
Do multiplication and division rank differently?
Answer
They rank equally, so left to right applies. The answer is .
Full solution
Leo computed first, then .
Multiplication and division are the same step, so neither outranks the other and they are carried out in the order they appear. The division is further left:
, then .
The mnemonic “PEMDAS” invites his mistake by listing M before D. They belong on one line — and so do the A and the S.
Frequently asked questions
What is the order of operations?
Parentheses first, then exponents, then multiplication and division left to right, then addition and subtraction left to right.
Why is 2 + 3 × 4 equal to 14?
Multiplication comes before addition, so 3 × 4 = 12 is evaluated first, then 2 + 12 = 14.
Does multiplication always come before division?
No. They rank equally and are done left to right. In 12 ÷ 3 × 2 the division comes first because it is further left, giving 8.
What do parentheses do?
They override the order. Whatever is inside them is evaluated first, so (2 + 3) × 4 is 20 rather than 14.
Is the order a rule of nature?
No, it is an agreement. It was chosen so that everyone reads the same expression the same way, and parentheses let you say something different when you need to.
Standards alignment
This lesson covers the following Common Core State Standards for Mathematics.
- CCSS.MATH.CONTENT.5.OA.A.1Operations and Algebraic ThinkingUse parentheses, brackets, or braces in numerical expressions, and evaluate expressions with these symbols.
- CCSS.MATH.CONTENT.5.OA.A.2Operations and Algebraic ThinkingWrite simple expressions that record calculations with numbers, and interpret numerical expressions without evaluating them.