Télécharger la présentation
## Course 1

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Course 1**2-1 Variables and Expressions Warm Up Problem of the Day Lesson Presentation Course 1**Warm Up**Simplify. 1. 4 + 7 3 1 2. 87 15 5 3. 6(9 + 2) + 7 4. 35 7 5 24 84 73 25**4 31**52 Problem of the Day How can the digits 1 through 5 be arranged in the boxes to make the greatest product? **Vocabulary**variable constant algebraic expression**A variable is a letter or symbol that represents a quantity**that can change. A constant is a quantity that does not change.**Algebraic Expressions**NOT Algebraic Expressions An algebraic expression contains one or more variables and may contain operation symbols. So p 7 is an algebraic expression. 150 + y 85 ÷ 5 35 w + z 10 + 3 5 To evaluate an algebraic expression, substitute a number for the variable and then find the value.**y**5 y 16 80 27 y = 27; 5 = y = 35; 5 = 35 Additional Example 1A: Evaluating Algebraic Expressions Evaluate the expression to find the missing values in the table. Substitute for y in 5 y. y = 16; 5 16 = 80 27 135 135 175 35 175 The missing values are 135 and 175.**z**z 5 + 42 Substitute for z in z 5 + 42. 20 20 45 60 Additional Example 1B: Evaluating Algebraic Expressions Evaluate the expression to find the missing values in the table. z = 20; 20 5 + 16 = 20 25 z = 45; __ 5 + 16 = __ 45 25 60 28 z = 60; __ 5 + 16 = __ 28 The missing values are 25 and 28.**x**x 9 18 2 x = 36; 9 = 36 x = 54; 9 = 54 Check It Out: Example 1A Evaluate the expression to find the missing values in the table. Substitute for x inx 9. x = 18; 18 9 = 2 4 36 4 6 54 6 The missing values are 4 and 6.**z**8 z + 23 Substitute for z in 8 z + 23. 7 64 9 11 Check It Out: Example 1B Evaluate the expression to find the missing values in the table. z = 7; 8 7 + 8 = 64 9 80 z = 9; 8 __+ 8 = __ 80 11 96 z = 11; 8 __ + 8 = __ 96 The missing values are 80 and 96.**Instead of . . .**You can write . . . 35 y Writing Math When you are multiplying a number times a variable, the number is written first. Write “3x” not “x3.” Read 3x as “three x.” You can write multiplication and division expressions without using the symbols and . x 3 x 3 x(3) 3x 35 ÷ y**Additional Example 2: Evaluating Expressions with Two**Variables A rectangle is 4 units wide. How many square units does the rectangle cover if it is 3, 4, 5, or 6 units long? Make a table to help you find the number of square units for each length. 3 x 4 = square units 12 16 4 x 4 = square units 16 20 5 x 4 = square units 20 24 6 x 4 = square units 24 The rectangle will cover 12, 16, 20, or 24 square units.**Check It Out: Example 2**A rectangle is 3 units wide. How many square units does the rectangle cover if it is 2, 3, 4, or 5 units long? Make a table to help you find the number of square units for each length. 2 x 3 = square units 6 9 3 x 3 = square units 9 12 4 x 3 = square units 12 15 5 x 3 = square units 15 The rectangle will cover 6, 9, 12, or 15 square units.**Lesson Quiz**1. Evaluate the expression to find the missing values in the table. 95 44 20 2. A rectangle is 6 units wide. How many square units does the rectangle cover if it is 2, 3, 4, or 5 units long? 12 18 24 30