1. Splash Screen

2. Five-Minute Check (over Lesson 2–6) Main Idea
Key Concept: Addition Properties
Example 1: Name Addition Properties
Example 2: Use Properties to Add Whole Numbers
Example 3: Use Properties to Add Decimals
Example 4: Partial Sums of 10
Lesson Menu

3. I will use Associative and Commutative Properties to add whole numbers and decimals mentally.
Main Idea/Vocabulary

4. KC 1

5. Name Addition Properties
Identify the addition property used to rewrite the problem below.
14 + (26 + 5) = ( ) + 5
The grouping of the numbers to be added changes.
Answer: This is the Associative Property of Addition.
Example 1

6. Identify the addition property used to rewrite the problem below. =
Commutative Property
Associative Property
Identity Property
Distributive Property A B C D
Example 1

7. Use Properties to Add Whole Numbers
Aisling counted 21 gray cars, 13 white cars, and 19 red cars. How many cars did she count in all?
Since you can easily add 21 and 19, change the order and group those numbers together. =
Commutative Property
= ( ) + 13
Associative Property =
Add 21 and 19 mentally.
= 53
Add 40 and 13 mentally.
Answer: So, Aisling counted 53 cars in all.
Example 2

8. Louanne saw 12 scary movies, 15 action movies, and 8 comedy movies last year. How many did she see in all?
15 movies
20 movies
35 movies
40 movies A B C D
Example 2

9. Use Properties to Add Decimals
Use properties of addition to find mentally.
Since = 2, group 1.7 and 0.3 together. =
Commutative Property
= ( ) + 0.6
Associative Property =
Add 1.7 and 0.3 mentally.
= 2.6
Add 2.0 and 0.6 mentally.
Example 3

10. Use properties of addition to find 5.1 + 0.2 + 0.9.
6.2
6.0
5.8
5.1 A B C D
Example 3

11. Use properties of addition to find 24 + 17 mentally.
Partial Sums of 10
Partial Sums of 10
Use properties of addition to find mentally.
= (20 + 4) + (10 + 7)
24 = and 17 = =
Commutative Property
= ( ) + (4 + 7)
Associative Property =
Add inside the parentheses.
= 41
Add 30 and 11 mentally.
Example 4

12. Use properties of addition to find 35 + 26.50 60 61 A B C D
Example 4

13. End of the Lesson
End Lesson

14. Five-Minute Check (over Lesson 2–6) Image Bank Math Tool Chest
Add and Subtract Decimals
Resources

15. Find 51.37 + 8.2. 59.57 60 58.57 58.6 (over Lesson 2–6) A B C D
Five Minute Check 1

16. Find 18.35 – 5.62. 12.74 12.73 13.73 12.75 (over Lesson 2–6) A B C D
Five Minute Check 2

17. Find 5.05 – 2.131. 3.92 2.019 2.919 2.28 (over Lesson 2–6) A B C D
Five Minute Check 3

18. Find 3.19 + 4.016. 7.201 7.31 7.206 7.1 (over Lesson 2–6) A B C D
Five Minute Check 4

19. End of Custom Shows