Intro to Order of Operations and Aunt Sally (PEMDAS)

Lesson Plan - Get It!

Audio:

Chances are, by this point in your math journey, you have run into a problem or two where you are mixing operations in the problem.

For example, 2 + 4 x 3. You may think you go from left to right to solve it, the same way you read a sentence. However, math rules are very different, and simply trying to solve a problem like the one above from left to right is a big no-no.

Instead, there is a specific ORDER in which you should solve each operation within problems that have multiple operations.

"What is that order?" you ask? Well, cue in our dear Aunt Sally!

We will use the phrase "Please Excuse My Dear Aunt Sally" (or PEMDAS) to remind you to solve problems in the following order:

• P - Parentheses
• E - Exponents
• M - Multiplication
• D - Division
• A - Addition
• S - Subtraction

This means take care of ANY operations within parentheses first, then exponents (or powers), then multiplication and division from left to right, and, finally, addition and subtraction from left to right.

Here are some examples using dear Aunt Sally's rules:

Example 1

3 + (8 – 5)
3 + (3)  < Take care of parentheses first.
= 6

Example 2

(10 + 6) x 3 – 4²
16 x 3 – 4²   16 x 3 – 16  < E: Next take care of any exponents.
48 - 16  < M/D: Take care of any multiplication and division from left to right.
32  

Example 3

22 - (3 x 4) + 10 – (9 – 1)
22 - 12 + 10 - 8  10 + 10 - 8  20 - 8          12

Here are a few more dear Aunt Sally examples below, in Math Antics – Order of Operations:

After viewing the video, it is time to put this info into practice!