Order of Operations: The Power of the Parentheses

Our objective today was the same.  I wanted my classes to understand the impact that changing the order has when performing a series of operations.  

So, we continued working with the Order of Operations using PEMDAS.  First, we finished up the worksheet "A Skeleton of My Former Self."  We worked the problems on our desk using dry erase markers.  The kids will do a hundred math equations if they can write on their desk!  :-)

Then I posed new problems.  These problems were equations that were missing the needed parenthesis.  Our first problem was:

57 - 15 + 17 = 25

1. I asked the classes to solve this problem based on PEMDAS.  Once we discovered that we just needed to add/subtract from left to right, I asked them if the answer they found equaled 25.  The answer was "no" and they were shocked!  
2. Next, I placed the parentheses on the equation:  

57 - (15 + 17) = 25

When performing the operation within the parentheses FIRST.... the equation worked!

We spent the remainder of class working with groups of equations that were missing the parentheses and determining exactly where the parenthesis needed to placed.  The kids loved it (it may have just been the markers, but I like to think they actually liked the math)!

To finish the class, the students had to fill out an exit ticket.  Today's prompt was:

If math parentheses could talk, how would they explain their work in mathematical equations?

Have a great weekend!