Order of Operations Party

Imagine you want to throw a party.  What will you need to buy?  If I wanted to throw a party for our math class (since everybody mastered Order of Operations), here is what I would need:

I know that each of these items costs $5.  How much will the party cost?

Well, I know that I need to buy 2 veggie trays.  For the next three items, I need 4 each.  Here's what that looks like in numbers and operations:

5(2 + 3 x 4)

In your journal, use order of operations to find out how much this party would cost.  Circle your answer.

In the Real World

We have seen how the order of operations is important in math.  In the video from Brain Pop, you saw that the order of operations is also important in baking.  This example is helpful for demonstrating, in an accessible way, how the order in which you do things makes a difference for the final outcome.

Imagine you are trying to explain why the order of operations is important in math to a student in another class that doesn't understand, and hasn't seen this helpful example.  In your journal, write about another real world example in which the order of the steps makes a difference.  Try not to use baking as your example.  Explain how, in math, order matters, too.

Why do we need order of operations?

In this cartoon, the girl put the grocery items in the bag in the wrong order.  How could something as simple as loading groceries have a "right" order?  Well, if more delicate items like bread or eggs go in the bag first, and then a heavy item like milk or a watermelon goes in next, what would happen?  Mom certainly wouldn't be happy.  Although the cartoon above is a silly representation, do you see why it depicts the importance of the order of operations?

You all know that putting items in a grocery bag requires an order.  Did you know, though, that number operations require an order, too?  In math, we call this the Order of Operations.  In order to get the right answer on a complex math problem, we must do the individual operations in the right order:

• Parentheses
• Exponents
• Multiplication &
• Division
• Addition &
• Subtraction

For example, let's look at the problem  5 + 4 x 2.  What happens if we do the operations from left to right as they appear, without using the order of operations?  We would first do 5 + 4 and get 9.  Then we would do 9 x 2 and get 18.  Is this the correct answer?  No!  We need to use PEMDAS to determine the correct order of operations.  We should first do the multiplication:  4 x 2 = 8.  Then, we should add 5 + 8 = 13.  Do you see the difference?

In your math journal, come up with a complex math problem like my example.  Using more than two operations in your problem, show how using the incorrect order of operations gives you the wrong answer.  Be sure to do the problem correctly, and circle your answer.