Learn to write algebraic expressions.

  + – Word Phrases Expression n + 5 x  11 3m a or a  7 7 a number plus 5 add 5 to a number n + 5 sum of a number and 5 5 more than a number a number increased by 5 a number minus 11 subtract 11 from a number x  11 difference of a number and 11 11 less than a number a number decreased by 11 3 times a number 3m 3 multiplied by a number product of 3 and a number a number divided by 7 or a  7 a 7 7 divided into a number quotient of a number and 7

Example 1: Translating from Algebra to Words Give two ways to write each algebra expression in words. A. 9 + r B. q – 3 the sum of 9 and r the difference of q and 3 9 increased by r 3 less than q C. 7m D. j  6 the product of m and 7 the quotient of j and 6 m times 7 j divided by 6

Additional Examples 1A and 1B: Translating Word Phrases into Math Expressions Write an algebraic expression for each word phrase. A. the product of 8 and n the product of 8 and n 8 • n 8n B. w decreased by 9 w decreased by 9 w – 9 w – 9

Try This: Examples 1A and 1B Write an algebraic expression for each word phrase. A. the sum of h and 88 the sum of h and 88 h + 88 h + 88 B. the quotient of f and 6 quotient of f and 6 f  6 f 6

Additional Examples 1C and 1D: Translating Word Phrases into Math Expressions Write an algebraic expression for each word phrase. C. 3 increased by the difference of p and 5 3 increased by the difference of p and 5 3 + (p – 5) 3 + (p – 5) D. 24 decreased by the product of 6 and q 24 decreased by the product of 6 and q 24 – (6 • q) 24 – 6q

Additional Example 2: Interpreting Which Operation to Use in Word Problems A. Jared works for $8 an hour at the store for h hours. Write an expression to determine how much money Jared earned. 8h Multiply 5 by h hours. B. How much money will he earn if he works a total of 10 hours? 8 • 10 = 80 Evaluate the expression for h = 10. Jared earned $80.

Try This: Example 2 A. A taxi-cab driver charges a base fee of $2, plus an additional $0.25 per mile. Write an expression to determine the fare. 2 + .25m $2 plus .25 per mile. B. If a passenger needs to travel 12 miles, how much money will they need to pay? 2 + .25(12) =$5 Evaluate the expression for m = 12. It will cost $5 to travel 12 miles.

Additional Example 3B: Writing and Evaluating Expressions in Word Problems B. The cost to rent out a bowling alley is $240. If the cost will be shared equally among all of the people who attend the party, how much will it cost each person if 12, 20, 40 or 100 people attend? $240  n Separate the cost into n equal groups. 240  n In dollars n 240  n Cost Evaluate for n = 12, 15, 16, and 20. 12 240  12 $20 20 240  20 $12 40 240  40 $6 100 240  100 $2.50

Write an algebraic expression for each word phrase. 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 and used it to solve the problem. 4. Karen buys n raffle tickets for $0.50 each. If she buys 13 of them, how much will they cost? k – 5 x 11 4(n + 5) 0.50n; $6.50