1. Evaluating Expressions R. Portteus

2. Order of Operations Review How do you follow the order of operations?

3. Order of Operations 1.( ) 2.Exponents Ex. 3² = 3 x 3 = 9 3.x or ÷, from Left to Right 4.+ or ─, from Left to Right

4. Order of Operations Review 20 ÷ 4 x 2 3 + (5 - 8) = 20 ÷ 4 x 2 3 + (5 - 8) = A.43B. 27 C. 1D. 37

5. 20 ÷ 4 x 2 3 + (5 - 8) = 20 ÷ 4 x 2 3 + (5 - 8) = A.43 B.27 C.1 D.37 20 ÷ 4 x 2 3 + (5 - 8) = 20 ÷ 4 x 2 3 + (-3) = 20 ÷ 4 x 8 + (-3) = 5 x 8 + (-3) = 40 + -3 = 37

6. Evaluating Expressions Vocabulary: –Variable – A symbol, usually a letter of the alphabet, such as the letter n, that is used to represent a number. –Variable expression (A.K.A. - Algebraic Expression) – An expression, such as n – 5, that consists of one or more numbers and variables along with one or more arithmetic operations. (Note: No equal sign) –Evaluate a Variable Expression – write the expression, substitute a number for each variable, and simplify the result.

7. How do you describe a variable expression? Variable Expression MeaningOperation 5x, 5·x, (5)(x) (same as x·5) 5 times xMultiplication 5 divided by xDivision 5 + x (same as x + 5) 5 plus xAddition 5 – x5 minus xsubtraction

8. Journal Reflection Evaluate Expressions VideoVideo Write your reflection from the video.

9. Journal Reflection Let’s watch a short videovideo Write your reflection from the video.

10. How do we evaluate expressions for each math operation, + - x ÷ ?

11. Substitute 4 for n. Simplify Simplify (means to solve the problem or perform as many of the indicated operations as possible.) Solution: Substitute 4 for n. Simplify Solution: Evaluate a Variable Expression with each operation Example 1: Evaluate each expression when n = 4. a. n + 3 n + 3 = 4 + 3 = 7 b.n – 3 n – 3 = 4 – 3 = 1

12. Substitute 8 for x. Simplify Solution: Using parenthesis is the preferred method to show multiplication. Additional ways to show multiplication are 5 · 8 and 5 x 8. Substitute 8 for x. Simplify Recall that division problems are also fractions – this problem could be written as: Evaluate an Algebraic Expression Example 2: Evaluate each expression if x = 8. a.5x 5x = 5(8) = 40 b.x ÷ 4 x ÷ 4 = 8 ÷ 4 = 2

13. Let’s go to the next level! What if an expression has more than one variable? How do I evaluate expressions with more than one variable?

14. Substitute 4 for x; 6 for y. simplify Solution: Evaluating Expressions with more than one variable Example 3: Evaluate each expression if x = 4, y = 6, and z = 24. a.5xy 5xy = 5(4)(6) = 120 b. = 4 Solution: Substitute 24 for z; 6 for y. Simplify.

15. A A A A A A Now You Try… Evaluate each expression given that a = 6, b = 12, and c = 3. 1.4ac 2.a ÷ c 3.a + b + c 4.ba 5.b – c 6.c ÷ b

16. Substitute the value for a = 6 and c = 3 into the problem and multiply Click to return to “You try it” slide You Try #1 Evaluate each expression given that a = 6, b = 12, and c = 3. 1.4ac 4ac = 4(6)(3) = (24)(3) = 72

17. Substitute the value for a = 6 and c = 3 into the problem and divide Click to return to “You try it” slide You Try #2 Evaluate each expression given that a = 6, b = 12, and c = 3. 2.a ÷ c a ÷ c = 6 ÷ 3 = 2

18. Substitute the value for a = 6, b=12, and c = 3 into the problem, then add. Click to return to “You try it” slide You Try #3 Evaluate each expression given that a = 6, b = 12, and c = 3. 3.a + b + c a + b + c = 6 + 12 + 3 = 18 + 3 = 21

19. Substitute the value for b=12 and a = 6 into the problem, then multiply. Click to return to “You try it” slide You Try #4 Evaluate each expression given that a = 6, b = 12, and c = 3. 4.ba ba = (12)(6) = 72

20. Substitute the value for b=12 and a = 3 into the problem, then subtract. Click to return to “You try it” slide You Try #5 Evaluate each expression given that a = 6, b = 12, and c = 3. 5.b - c b – c = 12 – 3 = 9

21. Substitute the value for c=3 and b = 12 into the problem, then Divide Note: It is better to rewrite this division problem as a fraction. This fraction can now be reduced to its simplest form. Substitute the value for c=3 and b = 12 into the problem, then Divide Note: It is better to rewrite this division problem as a fraction. This fraction can now be reduced to its simplest form. Divide both numerator and denominator by the GCF = (3) to reduce this fraction. It is OK to have a fraction as an answer. Click to return to “You try it” slide You Try #6 Evaluate each expression given that a = 6, b = 12, and c = 3. 6.c ÷ b

22. Summary To evaluate expressions: 1.Replace a variable with a number 2.Follow order of operations to find the solution. 3.Follow the algorithms for integers.

23. Exit Ticket

24. 5 x 6 = 30 9 x 5 = 45 2(8) – 4 = 18/3 + 18 = 16 – 4 = 12 6 + 18 = 24 3 x 4 = 12 10 ÷ 2 + 10 = 5 + 10 = 15

26. 9(4) – 25 = 36 – 25 = 11 9 x 9 = 81 56/8 – 5 = 7 – 5 = 2 14 + 3(6) = 14 + 18 = 32

27. Homework Homework Evaluate Expressions 3 Terms Add/Subtract A and B herehere