1. 1-4 Properties and Mental Math 9/20/11 Warm Up Find each sum or product. 1. 17 + 15 2. 29 + 39 3. 8(24) 4. 7(12) 5. 3(91) 6. 6(15) 32 68 192 84 273 90

2. 1-4 Properties and Mental Math Vocabulary Commutative Property 18 + 9 = 9 + 18 15 x 2 = 2 x 15

3. 1-4 Properties and Mental Math Vocabulary Associative Property (17 + 2) + 9 = 17 + (2 + 9) (12 x 2) x 4 = 12 x (2 x 4)

4. 1-4 Properties and Mental Math Simplify 17 + 5 + 3 + 15. 17 + 5 + 3 + 15 Look for sums that are multiples of 10 40 Use the Commutative Property. 17 + 3 + 5 + 15 (17 + 3) + (5 + 15) Use mental math to add. 20 + 20 Use the Associative Property to make groups of compatible numbers.

5. 1-4 Properties and Mental Math Simplify 4  13  5. 4  13  5 Look for products that are multiples of 10 260 Use the Commutative Property. 13  4  5 13  (4  5) Use mental math to multiply. 13  20 Use the Associative Property to group compatible numbers.

6. 1-4 Properties and Mental Math Simplify 12 + 5 + 8 + 5. 12 + 5 + 8 + 5 Look for sums that are multiples of 10 30 Use the Commutative Property. 12 + 8 + 5 + 5 (12 + 8) + (5 + 5) Use mental math to add. 20 + 10 Use the Associative Property to make groups of compatible numbers.

7. 1-4 Properties and Mental Math Vocabulary Distributive Property 6(10 + 4) = (6 x 10) + (6 x 4)

8. 1-4 Properties and Mental Math Use the Distributive Property to find the product. 6  35 6  35 = 6  (30 + 5) “Break apart” 35 into 30 + 5. = 210 Use the Distributive Property. = (6  30) + (6  5) Use mental math to add. = 180 + 30 Use mental math to multiply.

9. 1-4 Properties and Mental Math Use the Distributive Property to find the product. 9  87 9  87 = 9  (80 + 7) “Break apart” 87 into 80 + 7. = 783 Use the Distributive Property. = (9  80) + (9  7) Use mental math to add. = 720 + 63 Use mental math to multiply.

10. 1-4 Properties and Mental Math Use the Distributive Property to find the product. 4  27 4  27 = 4  (20 + 7) “Break apart” 27 into 20 + 7. = 108 Use the Distributive Property. = (4  20) + (4  7) Use mental math to add. = 80 + 28 Use mental math to multiply.

11. 1-4 Properties and Mental Math Lesson Quiz Simplify. 1. 18 + 24 + 2 + 6 2. 10  5  3 3. 13 + 42 + 7 + 8 Use the Distributive Property to find each product. 4. 8  125. 6  15 6. 5  347. 3  71 15050 70 96 90 170213

12. 1-4 Properties and Mental Math Homework Page 24-25: 32-54 even