6.2 – More Patterns and Expressions Grade 5 – Write and evaluate expressions involving multiplication, addition, and subtraction

Set the Purpose You have already evaluated numerical and algebraic expressions. Today you will learn how to evaluate algebraic expressions with more than one operation.

Pose the Problem The rental car company charges 40 BD as a base to rent a car and 2 BD for every kilometer driven. How much would it cost to rent a car and drive 30 kilometers? What information are you given to solve this problem? How can you use this information to find the total cost of the rental? What expression can you write to show this?

Continued The rental car company charges 40 BD as a base to rent a car and 2 BD for every kilometer driven. How much would it cost to rent a car and drive 30 kilometers? Final Cost __________________ Cost for Kilometers Driven ____________ Kilometers Driven 30 40 75 100

Word Problem Bob’s Electrical Repair $55 Fee $65 per hour The total cost is the fee plus the charge per hour times the number of hours. Write an expression for the total cost. Let H represent the number of hours.

Word Phrases & Algebraic Expressions Word Phrase Algebraic Expression Five times a number, plus two Two less than five times a number Two more than five times a number Two minus five times a number

TIP Sometimes a word phrase can be interpreted in different ways. The word phrase below can be interpreted in two different ways. Parentheses are used to make the algebraic expressions clear. Word Phrase: five times a number plus 2 Algebraic Expressions: (5 x n) + 2, or 5 x (n + 2)

Practice Three times a number, plus 10 Four less than a number times 2 Eight plus a number times 5 Forty minus two times a number

Practice Nine times a number, minus six Seven less than a number times three Four more than a number, times twelve Eight plus a number times sixteen

Practice Evaluate the expression for r = 6 and h = 42 (8 + r ) x 3 9r – 2h

Homework 6.3 Worksheet