1. CONFIDENTIAL1 Warm-up: 1.) 98 - 12 = 2.)49 + 13 = 3.)9 - 6 ÷ 3 = 4.)4 + 5 x 8 = 5.)7 2 - 20 = Today we will learn How to Evaluate Expressions

2. CONFIDENTIAL2 Remember... ORDER OF OPERATIONS A set of rules that tells us which operation to perform first We can recall the Order of Operations as P E M D A S Parentheses Exponents Multiplication Division Addition Subtraction

3. CONFIDENTIAL3 PEMDASPEMDAS We multiply and divide in order from left to right. THEN we add and subtract in order from left to right. 63 ÷ (10 - 3) x 3 + 6 63 ÷ 7 x 3 + 6 Do the Parentheses first Then we Divide 9 x 3 + 6Then we Multiply Finally we Add 27 + 6 32

4. CONFIDENTIAL4 ALGEBRA is a mathematical language in which symbols represent numbers and they are related by operations. We call the symbols "VARIABLES". n t x p "VARIABLES" are usually letters which are used to represent Numbers. q w c b y x t h w d f z u k l x t q m h s s

5. CONFIDENTIAL5 3 + n is an "ALGEBRAIC EXPRESSION" Numbers Operations Variables Algebraic Expressions consist of Numbers, Operations, and Variables.

6. CONFIDENTIAL6 The VARIABLES in an expression can be replaced with any number. 3 + x If I substitute a 5 for the x........... I have 3 + 5 or 8 This is how we Evaluate (or find the value of) the Expression

7. CONFIDENTIAL7 Let's Evaluate the Algebraic Expression 16 + b if b = 25 We replace b with the number 25 16 + b = 16 + 25 = 41 The Value of the Algebraic Expression when b = 25 is 41

8. CONFIDENTIAL8 Let's Evaluate the Algebraic Expression x - y if x = 64 and y = 27 In other words, in the Expression x - y, let's replace x with the number 64 and replace y with the number 27. x - y = 64 - 27 = 37

9. CONFIDENTIAL9 There are several ways to show multiplication. 2 3 means 2 x 3 6t means 6 x t st means s x t We always write the number BEFORE the variable..

10. CONFIDENTIAL10 Evaluate the expression 5t + 4 if t = 3 Replace t for the number 3 5t + 4 = 5 x 3 + 4 = 15 + 4 Remember PEMDAS! = 19

11. CONFIDENTIAL11 Your Turn! Evaluate each expression if a = 6 and b = 4 1.)a + 8 = 2.)a - b = 3.)a x b = 4.)2a - 5 =

12. CONFIDENTIAL12 Complete the Table Algebraic Expressions 7a - 3b 2w - 3x + 4y Name the Variables Name the Numbers Name the Operations (1) (2)

13. CONFIDENTIAL13 Distance can be calculated using the formula D = rt where r = rate and t = time Find the distance (D) from Dallas to Houston if I am travelling in my car at a rate (r) of 60 miles per hour AND it take me 4 hours (t) without stopping. D = r t Remember that rt means r x t D = r t D = 60 x 4 D = 240 That's 240 miles!

14. CONFIDENTIAL14 Find the value of 2x 2 - 6 x 2 if x = 7 First replace the x with the number 7 Remember PEMDAS and handle the exponents first. Do the multiplication in the order in which it occurs. Finally, do the subtraction.

15. CONFIDENTIAL15 Which one of these expressions is NOT an Algebraic Expression? 1.)ab 2.)16 + 3 3.) 3x + 2 4.)7x

16. CONFIDENTIAL16 1.)In the Algebraic Expression 3x + 5 - 2y - what are the variables? -what are the numbers? -what are the operations? Evaluate each expression if a = 3, b = 12, and c = 8. 2.)7c ÷ 4 + 5a 3.)a 2 + 5b - c 2 4.)b 2 ÷ ( 3 c) 5.)15 + 9a ÷ 3.

17. CONFIDENTIAL17 Good Job! You worked hard today! Let's review what we learned..... Algebraic Expressions consist of Variables, Numbers, and Operations. Example: 4x + 8 Variables are symbols (usually letters) that represent Numbers. Example: x or y or a or b etc. The Variables in an Expression can be replaced with Numbers. Example: In the Expression 4b - 2, we can replace b with a Number. We can Evaluate Expressions by finding the value of the Expression when we replace the Variable with a Number. Example: When b = 3, the Expression 3b +10 has a value of 19 We can write multiplication as 3 x a OR 3a OR 3 a.