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. We worked on a worksheet entitled "Cleared for Takeoff" from the Feb/Mar 2013 issue of Mailbox Magazine. To introduce the process for using PEMDAS, we solved the first 4 problems together. I recorded this process:
PEMDAS: Cleared for Takeoff
Once we had completed these problems together, I asked the students to complete the last 10 on their own. Much thinking ensued! The most difficult part for my classes was NOT automatically working left to right. It was a struggle to have them refer back to PEMDAS to make sure they were doing the order correctly..... we got there though!
To finish off the class, I asked the students to:
Consider the following expression:
8 x 3 + [12 - (4 + 15 divided by 3)] + 9
Using words and/or numbers, describe the steps you would take to simplify the expression.