250 likes | 347 Views
Welcome Second Grade. While you wait for class to begin, click on the link to play a math game. Commutative Property- Day 1. Elluminate Rules. During the presentation please listen carefully. Try your best. Be respectful of your classmates.
E N D
Welcome Second Grade While you wait for class to begin, click on the link to play a math game. Commutative Property- Day 1
Elluminate Rules • During the presentation please listen carefully. • Try your best. • Be respectful of your classmates. • If you have a question, please raise your hand or type it in the chat box.
Today we will... • 2.8.2.A: Use the concept of equality and concrete objects to demonstrate understanding of the commutative and associative properties. • Essential Question: • How do I identify the Commutative Property, and how does this property help me with my math?
New Math Words This week, we will be looking at the commutative property of addition and multiplication. What is this? Let’s take a closer look…
Commutative Property The commutative property states that you can add numbers in any order and get the same sum. You can also multiply two numbers in any order and get the same product.
Let’s Take a Closer Look 5 + 4= 9 We can show the commutative property using two number sentences: 5 +4=9 4+5=9 You can also show it as one number sentence: 5 + 4= 4 + 5 4 + 5= 9
Circle the model that shows the commutative property of addition. 3 + 5 = 8 4 + 4 = 8 3 + 3 = 6 5 + 3 = 8
Let’s look at this example.. Complete the remainder of this number sentence: 3 + 4 = +
Now, Let’s Look at Multiplication... This array shows a multiplication sentence. 3 x =
Look at it another way. Now, the array has been turned on its side. The sentence now looks a little different 5 x =
We just found that... AND 3 x 5 = 15 5 x 3 = 15 You can also see the commutative property in multiplication. This property can be shown using the two number sentences above or as one number sentence: 3 x 5 = 5 x 3
Let’s look at this example... Complete the remainder of this number sentence: 2 x 4 = x
How can this property help us? You know that you can add or multiply numbers in any order. You can use this idea to find answers faster. 3 + 22 = ____ To find the answer faster, we can start with 22 and add 3 to get 25. 22 + 3 = 25
Adding 3 Addends We can also use the commutative property when adding 3 addends together. Look at the example below. 39 + 53 + 1 = ? We can switch 53 and 1 to add 39 and 1 together first. 40 + 53 = _____ 40 is a friendly number because it ends in 0.
Your Turn! Circle which two numbers would be easier to add first. Circles
Your Turn! What is the sum of 18 + 2?
Your Turn! What is the sum of 18 + 2? 20+ 25 =
Let’s Try Another One 28 + 34 + 2 = ? Circles
Let’s Try Another One 15 + 23 + 5 = ? Circles
Awesome Work!! • Now it’s time for you to try some on your own. • I will push out the Compass website to you so that you can complete this week’s pretest. • Don’t forget to log-in a complete your lessons this week if you have a learning path!
How to take the pre-test... • Log in to Compass with your username and password. • Click on Math Assignments. • Choose the folder: M2.A.2.8.2_Pre • Complete the pre-test. When you finish, make sure that you click and then “turn-in” to turn in your test.