What Is the Order of Operations?
Hello! My name is Bob, and I live with my wonderful Aunt Sally. My Aunt Sally does a great job of raising me. She fixes my meals, cleans the house and tucks me in at night. However, Aunt Sally often gets the order of these events mixed up. For example, yesterday my Aunt Sally cleaned the house, tucked me into bed and then made my meals.
I keep telling my Aunt Sally that order is important, but she doesn't seem to understand. Just like in math, there is a particular order that we work problems. Without this order, it is possible that we could all get different answers. The order that we use to simplify expressions in math is called the order of operations. The order of operations is the order in which we add, subtract, multiply or divide to solve a problem.
Order of Operations Steps
The steps we use to solve any mathematical expression are:
- Simplify all of the parentheses. This includes all forms of grouping symbols, such as brackets and braces, in addition to parentheses.
- Simplify all exponents.
- Simplify all multiplication and division from left to right. When simplifying the multiplication and division, work from left to right.
- Simplify all addition and subtraction from left to right. Again, when simplifying the addition and subtraction, work from left to right.
By following this order, we can all solve the problem and get the same solution.
PEMDAS
After explaining all of those rules to my Aunt Sally, she seems a little overwhelmed. However, I do have a shortcut to help her remember these steps. It's called PEMDAS.
It stands for:
- P - Parenthesis
- E - Exponents
- M - Multiplication
- D - Division
- A - Addition
- S - Subtraction
Remember that the steps for multiplication and division is one step. We work all of the multiplication and division in one step from left to right. Multiplication does not always come before division; they are worked in the order that they appear. This is also true for addition and subtraction. They are worked in the same step from left to right. An easy way for me to remember these steps is to remember the phrase Please Excuse My Dear Aunt Sally, where the:
- P - Parenthesis - Please
- E - Exponents - Excuse
- M - Multiplication - My
- D - Division - Dear
- A - Addition - Aunt
- S - Subtraction - Sally