Holt CA Course 1 1-4Properties of Numbers Vocabulary
Holt CA Course 1 1-4Properties of Numbers You can multiply numbers mentally by breaking apart one of the numbers and writing it as a sum or difference.
Holt CA Course 1 1-4Properties of Numbers Example 1: Identifying Properties of Addition and Multiplication Tell which property is represented. A. (2 6) 1 = 2 (6 1) B = 3 C = (2 6) 1 = 2 (6 1) The numbers are regrouped. Associative Property = 3 One of the addends is 0. Identity Property = 9 + 7The order of the numbers is switched. Commutative Property
Holt CA Course 1 1-4Properties of Numbers Example 2: Using Properties to Simplify Expressions Simplify each expression. Justify each step. A B. 20 9 = Commutative Property = 16 + (9 + 21) = Associative Property = 46 Add. 20 9 5 = 20 5 9 Commutative Property = 20 (5 9) = 20 45 Associative Property = 900 Multiply.
Holt CA Course 1 1-4Properties of Numbers Example 3: Using the Distributive Property to Multiply Mentally Use the Distributive Property to find 6(54). Method 1: Method 2: = (6 50) + (6 4) Rewrite 54 as = = 324 Use the Distributive Property. Multiply. 6(54) = 6(60 – 6) Rewrite 54 as 60 – 6. = (6 60) – (6 6) = 360 – 36 Use the Distributive Property. = 324 Subtract. Add. 6(54) = 6(50 + 4) Multiply.
Holt CA Course 1 1-4Properties of Numbers Check It Out! 1. Tell which property is represented. (5 1) 2 = 5 (1 2) The numbers are regrouped. Associative Property 2. Simplify each expression. Justify each step Commutative Property Associative Property(17+ 3)+ 14 = Add. = 34
Holt CA Course 1 1-4Properties of Numbers Check It Out! Example 3 Use the Distributive Property to find 8(19). Method 1: Method 2: = (8 10) + (8 9) Rewrite 19 as = = 152 Use the Distributive Property. Multiply. 8(19) = 8(20 – 1) Rewrite 19 as 20 – 1. = (8 20) – (8 1) = 160 – 8 Use the Distributive Property. Multiply. = 152 Subtract. Add. 8(19) = 8(10 + 9)