2-1 Variables and Expressions Course 1 6 th Grade Math HW: Page 50 #5-17 all

2-1 Variables and Expressions Course 1 Who did not take the Chapter 1 Test?

Course 1 Warm Up Lesson Presentation Lesson Presentation Problem of the Day 2-1 Variables and Expressions Course 1

Warm Up Simplify  3   15  (9 + 2)  7  Variables and Expressions Course 1

Problem of the Day How can the digits 1 through 5 be arranged in the boxes to make the greatest product?  Variables and Expressions Course 1

Today’s Learning Goal 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. p  7 is an algebraic expression. Algebraic Expressions NOT Algebraic Expressions y 85 ÷ 5 35  w + z  5 To evaluate an algebraic expression, substitute a number for the variable and then find the value. 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. y 5  y y = 16; 5  16 = y = 27; 5  = y = 35; 5  = 2-1 Variables and Expressions Course 1 The missing values are 135 and 175.

Evaluate the expression to find the missing values in the table. Additional Example 1B: Evaluating Algebraic Expressions Substitute for z in z  z z  z = 20; 20  = 8 z = 45; __  = __ z = 60; __  = __ Variables and Expressions Course 1 The missing values are 13 and 16.

Try This: 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 = Variables and Expressions Course 1 The missing values are 4 and 6.

Evaluate the expression to find the missing values in the table. Try This: Example 1B Substitute for z in 8  z + 2. z 8  z z = 7; 8  = 58 z = 9; 8  __+ 2 = __ z = 11; 8  __ + 2 = __ Variables and Expressions Course 1 The missing values are 74 and 90.

Multiplication and division can be written 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 2-1 Variables and Expressions Course 1

Find an expression for the table. Additional Example 2A: Finding an Expression 39  13 = 3 n  13 = 5 52  13 = 4 n  13 An expression is n  13, or. n Variables and Expressions Course 1

Find an expression for the table. Additional Example 2B: Finding an Expression 7 4 = 28 p = = 42 7 p An expression is 7 p, or 7p. 2-1 Variables and Expressions Course 1

Find an expression for the table. 21  3 = 7 u  3 =  3 = 14 u  3 An expression is u  3, or. u 3 Try This: Example 2A 2-1 Variables and Expressions Course 1

Find an expression for the table. Try This: Example 2B 4 5 = 20 n = = 32 4 n An expression is 4 n, or 4n. 2-1 Variables and Expressions Course 1

1. Evaluate each expression to find the missing values in the tables. Lesson Quiz: Part 1 x x x – 5 2. Find an expression for the table x7x 2-1 Variables and Expressions Course 1

Lesson Quiz: Part 2 3. Evaluate 8x for x = Evaluate 4x – 1 for x = Variables and Expressions Course 1