Properties of Numbers Use mental math to simplify –2 • 13 • 5. COURSE 3 LESSON 1-8 Use mental math to simplify –2 • 13 • 5. What you think It is easy to multiply with multiples of 10. –2 times 5 is –10, a multiple of 10. –10 times 13 is –130. So, –2 • 13 • 5 = –130. Commutative Property Why it works –2 • 13 • 5 = –2 • 5 • 13 Order of operations = –10 • 13 Simplify. = –130 1-8

Properties of Numbers Find each product. a. 7(t – 5) COURSE 3 LESSON 1-8 Properties of Numbers Find each product. a. 7(t – 5) 7(t – 5) = 7t – 7 • 5 Distributive Property Simplify. = 7t – 35 b. (d + 23)(–4) (d + 23)(–4) = d(–4) + 23(–4) Distributive Property = –4d + (–92) Simplify. = –4d – 92 Rewrite as a subtraction expression. 1-8

Properties of Numbers Simplify 9 • 13 + 11 • 13. What you think COURSE 3 LESSON 1-8 Simplify 9 • 13 + 11 • 13. What you think Combine 9 and 11 first because they are easy to add. 9 + 11 = 20. Multiply 20 by 13 to get 260. So, 9 • 13 + 11 • 13 = 260. Distributive Property Why it works 9 • 13 + 11 • 13 = (9 + 11) 13 Order of operations = (20)13 Simplify. = 260 1-8

Properties of Numbers COURSE 3 LESSON 1-8 Use the Distributive Property to rewrite each expression. 1. 8(a + 2) 2. –2(3x + 1) 3. 4 • 3 + 6 • 3 4. (6 – r)(–4) 5. 5 • 1 + 5 • 9 8a + 16 –6x – 2 (4 + 6)3 –24 + 4r 5(1 + 9) 1-8