The Calculations' Order (PEMDAS)
PEMDAS is an acronym for the words:
- Parentheses
- Exponents
Multiplication
Division
Addition
Subtraction
It refers to the order in which these calculations need to be performed.
Info
- Parentheses need to be calculated before Exponents.
- Exponents need to be calculated before Multiplication and Division.
- Multiplication and Division need to be calculated in the order they occur from left to right.
- Multiplication and Division need to be calculated before Addition and Subtraction.
- Addition and Subtraction need to be calculated in the order they occur from left to right.
Examples 1
$4\cdot5+2=?$
calculations' order:
- Multiplication before Addition
$4\cdot5+2$ $=20+2$ $=22$
$14-9+6=?$
calculations' order:
- Addition and Subtraction in the order they occur
$14-9+6$ $=5+6$ $=11$
$9\div3\cdot2=?$
calculations' order:
- Multiplication and Division in the order they occur
$9\div3\cdot2$ $=3\cdot2$ $=6$
$12-8\cdot5\div4+7=?$
calculations' order:
- Multiplication and Division before Addition and Subtraction
- Multiplication and Division in the order they occur
- Addition and Subtraction in the order they occur
$12-8\cdot5\div4+7$ $=12-40\div4+7$ $=12-10+7$ $=2+7$ $=9$
Remember
If there are parentheses in the calculation, the same PEMDAS rule applies to the calculation inside these parentheses.
Examples 2
$(24\div4-8)\cdot7=?$
calculations' order:
- Parentheses before Multiplication and Division
- Multiplication and Division before Subtraction
$(24\div4-8)\cdot7$ $=(6-8)\cdot7$ $=-2\cdot7$ $=-14$
$(5+4)\cdot2^{3}=?$
calculations' order:
- Parentheses before Exponents
- Exponents before Multiplication
$(5+4)\cdot2^{3}$ $=9\cdot2^{3}$ $=9\cdot8$ $=72$
$14-(3+16\div4)\cdot2=?$
calculations' order:
- Parentheses before Multiplication and Division
- Multiplication and Division before Addition and Subtraction
$14-(3+16\div4)\cdot2$ $=14-(3+4)\cdot2$ $=14-7\cdot2$ $=14-14$ $=0$
$6\cdot(20\div2-7)+4^{2}=?$
calculations' order:
- Parentheses before Exponents
- Exponents before Multiplication and Division
- Multiplication and Division before Addition and Subtraction
$6\cdot(20\div2-7)+4^{2}$ $=6\cdot(10-7)+4^{2}$ $=6\cdot3+4^{2}$ $=6\cdot3+16$ $=18+16$ $=34$
Hint
The acronym PEMDAS can be memorized through the phrase:
Please Excuse My Dear Aunt Sally.
Info
In the UK they use the acronym BODMAS, which stands for:
- Brackets
- Orders
Divide
Multiply
Add
Subtract
and in Canada they use the acronym BEDMAS, which stands for:
- Brackets
- Exponents
Divide
Multiply
Add
Subtract
However, they all mean the same thing.