2-1 Variables and Expressions Course 1 Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day 2-1 Variables and Expressions Course 1 Warm Up Warm Up
2-1 Variables and Expressions Course 1 Learn to identify and evaluate expressions.
2-1 Variables and Expressions Course 1 Vocabulary variable constant algebraic expression
2-1 Variables and Expressions Course 1 A variable is a letter or symbol that represents a quantity that can change. A constant is a quantity that does not change.
2-1 Variables and Expressions Course 1 An algebraic expression contains one or more variables and may contain operation symbols. So p 7 is an algebraic expression. Algebraic Expressions NOT Algebraic Expressions y85 ÷ 5 35 w + z 5 To evaluate an algebraic expression, substitute a number for the variable and then find the value by using the order of operations.
2-1 Variables and Expressions Course 1 Evaluate the expression to find the missing values in the table. Additional Example 1A: Evaluating Algebraic Expressions Substitute for y in 5 y. y5 y
2-1 Variables and Expressions Course 1 Evaluate the expression to find the missing values in the table. Additional Example 1B: Evaluating Algebraic Expressions z z z = 20; = 36 z = 45; __ + 16 = __ z = 60; __ + 16 = __ The missing values are 61 and 76. Substitute for z in z
2-1 Variables and Expressions Course 1 Check It Out: Example 1A Evaluate the expression to find the missing values in the table. Substitute for x in x 9. x x x = 18; 18 9 = x = 36; 9 = x = 54; 9 = 36 The missing values are 4 and 6.
2-1 Variables and Expressions Course 1 Evaluate the expression to find the missing values in the table. Check It Out: Example 1B z 8 z z = 7; = 64 z = 9; 8 __+ 8 = __ z = 11; 8 __ + 8 = __ The missing values are 80 and 96. Substitute for z in 8 z
2-1 Variables and Expressions Course 1 You can write multiplication and division expressions without using the symbols and . Instead of... You can write... x 3 x 3 35 ÷ y x(3) 3x3x 35 y When you are multiplying a number times a variable, the number is written first. Write “3x” not “x3.” Read 3x as “three x.” Writing Math