1. Warm Up California Standards Lesson Presentation Preview

2. Warm Up Evaluate each expression for the given values of the variables. Which operation symbol goes with each word? 23 18 1 +    4. Sum 5. Product 6. Quotient 7. Difference 1. 9 y – 13 for y = 4 2. 6 n + 2 p for n = 2 and p = 3 3. 3 x – y for x = 1 and y = 2

3. AF1.1 Use variables and appropriate operations to write an expression, an equation, an inequality, or a system of equations or inequalities that represents a verbal description (e.g., three less than a number, half as large as area A). California Standards

5. Write an algebraic expression for each word phrase. Additional Example 1: Translating Word Phrases into Math Expressions A. 9 less than a number w 9 less than a number w w – 9 w – 9 B. 3 increased by the difference of p and 5 3 increased by the difference of p and 5 3 + ( p – 5 ) 3 + ( p – 5)

6. Write an algebraic expression for each word phrase. Check It Out! Example 1 A. 88 times the difference of h and 4 88 times the difference of h and 4 88 • ( h – 4) 88( h – 4) B. the quotient of a number f and 6 quotient of f and 6 f  6 f 6

7. Write a word phrase for the algebraic expression 9 – 3 c . Additional Example 2: Translating Math Expressions into Word Phrases 9 – 3 c 9 – 3 • c 9 minus the product of 3 and c 9 minus the product of 3 and c

8. Check It Out! Example 2 Write a word phrase for the algebraic expression 7 + 19 b . 7 + 19 b 7 + 19 • b 7 plus the product of 19 and b 7 plus the product of 19 and b

9. To solve a word problem, first interpret the action you need to perform and then choose the correct operation for that action.

10. A restaurant leased its banquet hall for a function. The cost was $10 per person. Write an algebraic expression to determine what the cost would be if n people attended the function. Then evaluate the expression for 20, 21, 22, or 23 people. Additional Example 3: Writing and Evaluating Expressions in Word Problems $10 • n Combine n equal amounts of $10. 10 n Cost in dollars 20 10( 20 ) $200 21 10( 21 ) $210 22 10( 22 ) $220 23 10( 23 ) $230 Evaluate for n = 20, 21, 22, and 23. Cost 10 n n

11. Gasoline costs $1.99 per n gallons. What will the cost be for 10, 12, 14, and 15 gallons? Check It Out! Example 3 $1.99 • n Combine n equal amounts of $1.99. 1.99 n Cost in dollars 10 1.99( 10 ) $19.90 12 1.99( 12 ) $23.88 14 1.99( 14 ) $27.86 15 1.99( 15 ) $29.85 Evaluate for n = 10, 12, 14, and 15. Cost 1.99 n n

12. Write a word problem that can be evaluated by the algebraic expression 27 + t , and evaluate the expression for t = 1.76. Additional Example 4: Writing a Word Problem from a Math Expression Possible answer: Amed bought a new sweater for $27 plus sales tax t . If the tax was $1.76, what was the total cost of the sweater? 27 + t 27 + 1.76 = 28.76 Substitute 1.76 for t. The total cost of the sweater was $28.76.

13. Write a word problem that can be evaluated by the algebraic expression 43 – d , and evaluate the expression for d = 10.24. Check It Out! Example 4 Possible answer: Tina bought a new jacket for $43 minus a store credit. If the store credit was $10.24, what did Tina pay for the jacket? 43 – d 43 – 10.24 = 32.76 Substitute 10.24 for d. Tina paid $32.76 for the jacket.

14. Lesson Quiz Write an algebraic expression for each word phrase. 1. 5 less than a number k 2. a number x divided by 11 3. 4 times the sum of n and 5 Write an algebraic expression to evaluate the word problem. 4. Karen buys n raffle tickets for $0.50 each. If she buys 13 of them, how much will they cost? k – 5 4( n + 5) 0.50 n ; $6.50 x 11