1.2 Writing Algebraic Expressions Standard: AF 1.1 Objective: Students translate phrases into expressions and vice versa. Numerical Expressions Numerical Expression Result Verbal Phrase Add 53 sum 8 The sum of 5 and 3 is 8. Subtract 10 7 difference 3 The difference of 10 and 7 is 3. Multiply 28 product 16 The product of 2 and 8 is 16. Divide 24 3 quotient 8 The quotient of 24 and 3 is 8. Operation Backwards Words Add 3 and 7 = 3 + 7 The sum of 3 and 7 = 3 + 7 3 increased by 7 = 3 + 7 The total of 3 and 7 = 3 + 7 3 more than 7 = 7 + 3 3 added to 7 = 7 + 3 Backwards Words 7 subtract 3 = 7 - 3 The difference of 7 and 3 = 7 - 3 7 decreased by 3 = 7 - 3 7 diminished by 3 = 7 - 3 7 less 3 = 7 - 3 7 less than 3 = 3 - 7 7 subtracted from 3 = 3 - 7 Translate the verbal phrase into a numerical expression and evaluate. 1) The difference of 8 and 1. 8 1 7 2) The product of 12 and 6. 12 6 72 3) The sum of 5 and 9. 5 9 14 4) The quotient of 12 and 3. 12 3 4 Write a verbal phrase that represents each algebraic expression below. 1) 10 x The difference of 10 and x. 2) 6m The product of 6 and m. 3) 12 y The quotient of 12 and y. 4) k 7 The sum of k and 7. Write a variable expression to represent the following if x represents your age. 1) Your age 5 years ago. x 5 2) Twice your age. 2x 3) Your age in 8 years. x 8 Translate the following phrases. 1) Five plus x minus 3 5+x-3 2) Three times y less 4 3y 4 3) Eight multiplied by y minus 7 8y - 7 4) The product of 10 and m decreased by 7 10m - 7 5) Four more than the quotient of x and 3 x 4 x 3 4 or 3 6) Six times m plus 8 6m + 8 Define a variable to represent the unknown and write the phrase as a variable expression. 1) 10 mph faster than the Honda Let x = the speed of the Honda x + 10 2) 7 inches shorter than Jill’s brother Let b = the height of Jill’s brother b-7 3) 5 acres larger than twice the size of my lot Let k = the size of my lot 2k + 5 4) $7.50 times the number of people plus a $20 group registration Let y = the number of people $7.5y + $20 Match each phrase with its variable expression. d 1) Twice the sum of x and 3 a) 2x 3 e 2) Two less than the product of 3 and x b 3) Three times the difference of x and 2 a 4) Twice a number x less 3 c 5) Two more than 3 times a number x b) 3 x 2 c) 3x 2 d) 2 x 3 e) 3x 2