Order of Operatiosn (PEMDAS)

By Brigid Del Carmen

In middle school math, students are required to memorize many formulas and processes, and using acronyms can be very helpful with these tasks. One such acronym, PEMDAS, can be used to remember the steps for Order of Operations. PEMDAS stands for Parentheses, Exponents, Multiplication, Division, Addition, Subtraction, which is the order students must follow when finding the value of expressions. Here's how to practice PEMDAS, and help your middle schooler complete her homework in half the time!

What You Need:

• multi-colored markers
• paper/pencil

What You Do:

1. At the top of the paper, ask your child to write the acronym PEMDAS, using a different color marker for each letter. Next to the word, write the symbol for the operation. Parentheses ( ) Exponents n² Multiplication • Division ÷ Addition + Subtraction -
2. Write a simple expression: 20 - 2² + (4 • 2)
3. Help your child find the value of the expression one step at a time.
   • Start with P.
   • Say: “Are there parentheses?” (yes) Solve what is in parentheses first, rewrite expression: 20 - 2² + 8
   • Put a check next to P.
   • Say: “Are there exponents?” (yes) Compute the exponent, rewrite expression: 20 – 4 + 8
   • Put a check next to E.
   • Say: “Is there multiplication or division?" (no)
   • Put a check next to M and D. (Note that if both of these operations did occur in the expression, they would be computed in order, from left to right. Multiplication and division stand on equal footing, as do addition and subtraction, and are always computed in order of appearance.)
   • Say: “Is there addition or subtraction?” (yes)
   • Solve, computing from left to right. In this case, subtraction (20 - 4) would come first, followed by 16 + 8.
   • The answer is 24.
4. Continue writing simple expressions, encouraging your middle-schooler to use PEMDAS as a checklist.

Tips:

1. Once your child has mastered simple expressions using PEMDAS, ask her to find the value of one expression two different ways. Compare the answers and note how important it is to follow PEMDAS.
2. Post PEMDAS on the fridge or bulletin board to be sure your middle-schooler doesn’t forget this very important acronym.
3. Come up with a phrase, such as "Please Excuse My Dear Aunt Sally" to help with remembering this important acronym!