Tuesday, March 11, 2014

Elvis and PEMDAS

Any math teacher who teaches the Order of Operations is familiar with the phrase, "Please Excuse My Dear Aunt Sally".  For the life of me, I don't know who Aunt Sally is or what she has done, but apparently we are to excuse her for the offense.  In my math classes, I use "Pale Elvis Meets Dracula After School".  Of course both of these examples are mnemonics or acronyms; so, the first letter of each word stands for something. 

P = parenthesis, E = exponents, M = multiplication, D = division,
A = addition, and S = subtraction

I have always taught the Order of Operations by just listing which procedures should be done first and in the order they were to be done.  But after viewing a different way on Pinterest (originally posted on Math = Love by Sara Hagen), I have changed my approach. Here is a chart with the details and the steps to "success" listed on the right.

Since multiplication and division as well as addition and subtraction equally rank in order, they are written side by side. What I like about this chart is that it clearly indicates to the student what they are to do and when.  To sum it up:

When expressions have more than one operation, follow the rules for the Order of Operations:
  1. First do all operations that lie inside parentheses.
  2. Next, do any work with exponents or radicals.
  3. Working from left to right, do all the multiplication and division.
  4. Finally, working from left to right, do all the addition and subtraction.
I have a new product that I recently added to my store entitled: Order of Operations - PEMDAS, A New Approach.  This ten page resource includes a lesson plan outline for introducing PEMDAS, an easy to understand chart for the students, an explanation of PEMDAS for the student as well as ten practice problems.  It is aligned with the fifth grade common core standard of 5.OA.1. Just click on the words under the cover page if it is something you might like.

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