1. 6th Grade Math: 1-4 HW

2. Course 1
1-5
Mental Math
6th Grade Math: 1-5 HW
Page 26 #13-24 all

3. 1-5 Mental Math Warm Up Problem of the Day Lesson Presentation
Course 1
Warm Up
Problem of the Day
Lesson Presentation

4. 1-5 Mental Math Warm Up Find each sum or product. 1. 17 + 15
Course 1
1-5
Mental Math
Warm Up
Find each sum or product.
3. 8(24)
4. 7(12)
5. 3(91)
6. 6(15) 32 68
192 84
273 90

5. 1-5 Mental Math Problem of the Day
Course 1
1-5
Mental Math
Problem of the Day
Determine the secret number from the following clues:
The number is a multiple of 5.
It is divisible by 3.
It is less than 200.
Its tens digit equals the sum of its other two digits.
165

6. Learn to use number properties to compute mentally.
Course 1
1-5
Mental Math
Today’s Learning Goal
Learn to use number properties to compute mentally.

7. Insert Lesson Title Here
Course 1
1-5
Mental Math
Insert Lesson Title Here
Vocabulary
Commutative Property
Associative Property
Distributive Property

8. Course 1
1-5
Mental Math
Mental math means “doing math in your head.”

9. COMMUTATIVE PROPERTY (Ordering)
Course 1
1-5
Mental Math
COMMUTATIVE PROPERTY (Ordering)
Words
Numbers
You can add or multiply numbers in any order. =
15  2 = 2  15

10. ASSOCIATIVE PROPERTY (Grouping)
Course 1
1-5
Mental Math
ASSOCIATIVE PROPERTY (Grouping)
Words
Numbers
When you are only adding or only multiplying, you can group any of the numbers together.
(17 + 2) + 9 = 17 + (2 + 9)
(12  2)  4 = 12  (2  4)

11. Course 1
1-5
Mental Math
Additional Example 1A: Using Properties to Add and Multiply Whole Numbers
A. Evaluate
Look for sums that are multiples of 10
Use the Commutative Property.
Use the Associative Property to make groups of compatible numbers.
(17 + 3) + (5 + 15)
Use mental math to add. 40

12. Course 1
1-5
Mental Math
Additional Example 1B: Using Properties to Add and Multiply Whole Numbers
B. Evaluate 4  13  5.
Look for products that are multiples of 10
4  13  5
13  4  5
Use the Commutative Property.
Use the Associative Property to group compatible numbers.
13  (4  5)
13  20
Use mental math to multiply.
260

13. 1-5 Mental Math Try This: Example 1A A. Evaluate 12 + 5 + 8 + 5.
Course 1
1-5
Mental Math
Try This: Example 1A
A. Evaluate
Look for sums that are multiples of 10
Use the Commutative Property.
Use the Associative Property to make groups of compatible numbers.
(12 + 8) + (5 + 5)
Use mental math to add. 30

14. 1-5 Mental Math Try This: Example 1B B. Evaluate 8  3  5.
Course 1
1-5
Mental Math
Try This: Example 1B
B. Evaluate 8  3  5.
Look for products that are multiples of 10
8  3  5
3  8  5
Use the Commutative Property.
Use the Associative Property to group compatible numbers.
3  (8  5)
3  40
Use mental math to multiply.
120

15. DISTRIBUTIVE PROPERTY
Course 1
1-5
Mental Math
DISTRIBUTIVE PROPERTY
Words
Numbers
When you multiply a number times a sum, you can
find the sum first and then multiply, or
multiply by each number in the sum and then add.
6  (10 + 4) = 6  14
= 84
6  (10 + 4) = (6  10) + (6  4) = =

16. Course 1
1-5
Mental Math
When you multiply two numbers, you can “break apart” one of the numbers into a sum and then use the Distributive Property.
Break the greater factor into a sum that contains a multiple of 10 and a one-digit number. You can add and multiply these numbers mentally.
Helpful Hint

17. Additional Example 2A: Using the Distributive Property to Multiply
Course 1
1-5
Mental Math
Additional Example 2A: Using the Distributive Property to Multiply
Use the Distributive Property to find the product.
A. Evaluate 6  35.
“Break apart” 35 into
6  35 = 6  (30 + 5)
Use the Distributive Property.
= (6  30) + (6  5)
Use mental math to multiply. = =
Use mental math to add.

18. Additional Example 2B: Using the Distributive Property to Multiply
Course 1
1-5
Mental Math
Additional Example 2B: Using the Distributive Property to Multiply
Use the Distributive Property to find the product.
B. Evaluate 9 x 87.
“Break apart” 87 into
9  87 = 9  (80 + 7)
Use the Distributive Property.
= (9  80) + (9  7)
Use mental math to multiply. = =
Use mental math to add.

19. 1-5 Mental Math Try This: Example 2A
Course 1
1-5
Mental Math
Try This: Example 2A
Use the Distributive Property to find the product.
A. Evaluate 4 x 27.
“Break apart” 27 into
4  27 = 4  (20 + 7)
Use the Distributive Property.
= (4  20) + (4  7)
Use mental math to multiply. = =
Use mental math to add.

20. 1-5 Mental Math Try This: Example 2B
Course 1
1-5
Mental Math
Try This: Example 2B
Use the Distributive Property to find the product.
B. Evaluate 6  43.
“Break apart” 43 into
6  43 = 6  (40 + 3)
Use the Distributive Property.
= (6  40) + (6  3)
Use mental math to multiply. = =
Use mental math to add.

21. Insert Lesson Title Here
Course 1
1-5
Mental Math
Insert Lesson Title Here
Lesson Quiz
Evaluate.
 5  3
Use the Distributive Property to find each product.
4. 8   15
6. Angie wants to buy 3 new video games. How much will she need to save if each game costs $27? 50
150 70 96 90
$81

22. Weekly Review!
Thank you for all of your hard work this week! I am so proud to be your teacher!  Mrs. Burgess