1. Algebra: Variables and Expressions 6.3 p. 449

2. Our Objectives? We will use skills from our previous lessons to evaluate algebraic expressions. We will evaluate expressions, using the process of Write SubstituteSolve

3. For the rest of the year, you will keep hearing three words, even in your sleep! Write SubstituteSolve

4. Vocabulary You have already had most of these…… Variable (vary is the root word……): A symbol, usually a letter, to represent some value Algebraic expression: An expression with numbers and variables Algebra: The abstract language of symbols and variables Evaluate: Find the value of; solve

5. You have a box of markers. You do not know how many there are in all, but you KNOW you have two red ones next to it! Unknown markers 2 Here is the expression for this situation: m + 2 With a sudden flash of memory, we remember we had 14 in the box.…how many do we have in all? m + 2 14 + 2 = 16 We will write an algebraic expression to represent this…to tell this story…

6. Evaluate One-Step Expressions p. 450 An algebraic expression has at least one variable. n + 2 The sum of a number and 2 5x 5(x) 5·x All show multiplication. Please avoid x as the variable! As we work through the examples, please notice each is 1)written with the variable 2)rewritten with the substituted value 3)evaluated using order of operations 1) 16 + b b=25 16 + 25 = 41 3) 6x x = ½ 2) x – y x = 64 y = 27 64 - 27 = 37 6(½) = 3 Write a + 8a – ba · b9c Substitute Solve 6 + 8 14 6 - 4 2 6 (4) 24 3

7. Adding more steps….p. 451 5(3) + 4 = 15 + 4 = 19 2 + 7 = 9 You will see fractions in most of these. Don’t stress. They are all multiplication. 1 2 2(12) - 5 24 – 5 = 19 50 – 1 = 49

8. Guided Practice p. 452

9. 3 + 4 = 7 9 – 4 = 5 3 + m z – m 12r 4m – 2 4(4) - 2 16 – 2 = 14 Guided Practice p. 452

10. 20 - 4(3)= 20 – 12 = $8 The amount of money that remains from a 20-bill after Malina buys 4 party favors for p dollars each is 20 – 4p. Evaluate this expression for p = 3 20 – 4p Guided Practice p. 452 How are numerical expressions different from algebraic expressions? Numerical expressions have only numbers and operation symbols. Algebraic expressions have at least one variable. Yes ? No

11. Today we have……….. Evaluated algebraic expressions What processes have we used? Write Substitute Solve (Evaluate) More steps will be added!!! Add your study pages to your notes!!!!