1. Lesson 1-1 Using Variables

2. Vocabulary A variable is a symbol, usually a letter, that represents on or more numbers. An algebraic expression is a mathematical phrase that can include numbers, variables, and operation symbols. An equation is a mathematical sentence that uses an equal sign. Workbook – page 2 An open sentence is an equation that contains one or more variables.

3. Textbook - page 4 Lined paper

4. Write an algebraic expression for each phrase. “Sum” indicates addition. Add the first number, n, and the second number, 8. n + 8 “Less than” indicates subtraction. Begin with the second number b. Then subtract the first number 6. b – 6. a. the sum of n and 8 b. six less than b Workbook – page 2

5. The sum of n and 7 n + 7 7 more than n n + 7 This follows the words This is the reverse order of the words The difference of n and 7 n - 7 7 less than n n-7 CAUTION

6. Textbook - page 5 Lined paper

7. Textbook - page 5 Lined paper

8. Define a variable and write an algebraic expression for each phrase. Relate:ten more than twice a number Define:Let y = the number. Write:2 y + 10 2y + 10 a. “ten more than twice a number.” Workbook – page 2

9. Textbook - page 5 Lined paper

10. Define:Let t = the number of tickets sold. Write an equation to show the total income from selling tickets to a school play for $5 each. Relate:The total incomeis 5 times the number of tickets sold. i = 5t Let i = the total income Write: i = 5 t Workbook – page 3

11. Textbook - page 5 Lined paper

12. Define:Let m = the number of miles traveled. Write an equation for the data in the table. Write: m = 20 g Gallons Miles 46810 80120160200 Let g = the number of gallons. Relate: Miles traveled equals 20 times the number of gallons. m = 20 g

13. Workbook – page 3

17. Keywords

18. Define a variable and write an algebraic expression for each phrase. Relate:three times a number minus 6 Write:3 n – 6 3n – 6 Define:Let n = the number. b. “three times a number minus six.” Additional Examples Lesson 1-1 Using Variables