Watch the youtube video below to see the start to this lesson. We started with the objective and then moved into a quick number sense routine. In just a couple of minutes, students explore combinations of 7, subitizing (knowing how many without counting) fingers patterns, and the commutative property. And they think it's so fun!
Today we are going to look at two problems to see if we can figure out the answer to our question today. Does it matter what the order of the two numbers is in an addition problem?
I sharpen 10 pencils. Then I sharpen 4 more pencils. How many pencils did I sharpen?
Partner talk guiding questions:
I sharpen 4 pencils. Then I sharpen 10 more pencils. How many pencils did I sharpen?
Partner talk: How is this problem the same as the first problem? How is it different?
“Before we solve the problem, who thinks the answer for both problems will be the same? Who thinks the answers will be different? Let’s take a quick vote!”
Watch the youtube video below for the student share portion of this lesson. I model the 2 problems with student help.
After we figured out the answers were the same, I asked the following questions:
Students solve 3 related fact story problems. The first 2 are addition facts (the commutative property) and the last one is a related subtraction problem for if students finish early.
The independent practice sheets are attached: IndPracticeCommutative.pdf. I left the numbers out so that you can write in the numbers that are most appropriate for your students! You can see how I created numbers for my differentiated math groups below.
See this youtube video for how a few girls work together to figure out how to solve a problem using groups of 10!
Students summarize what they learned with a partner.
Focus Question: Show your partner your story problems. How were your story problems the same? How were they different?