Evaluate algebraic expressions given variable values 6/15/11 Lesson 3 Evaluate algebraic expressions given variable values

Today’s Agenda 6/15/11 Review PEMDAS Example Problem Show common calculation errors Practice problems End-of-class assignment

Order of Operations PEMDAS lease xcuse y ear unt ally

PEMDAS Order of Operations arentheses xponent ultiplication ivision ddition ubtraction

Order of Operations PEMDAS ( ) 72 x - + -

Today’s Agenda 6/15/11 Review PEMDAS Example Problem Show common calculation errors Practice problems End-of-class assignment

Step 1: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 1: Plug the variable values into the expression. 2 7x + (12÷y)2 – y – (x+1) 6

Step 1: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 1: Plug the variable values into the expression. 7*2 + (12÷6)2 – 6 – (2+1)

Step 2: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 2: Evaluate the expression, using PEMDAS. 7*2 + (12÷6)2 – 6 – (2+1) Parentheses

Step 2: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 2: Evaluate the expression, using PEMDAS. 7*2 + (2)2 – 6 – (3)

Step 3: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 3: Evaluate the expression, using PEMDAS. 7*2 + (2)2 – 6 – 3 Exponent

Step 3: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 3: Evaluate the expression, using PEMDAS. 7*2 + 4 – 6 – 3

Step 4: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 4: Evaluate the expression, using PEMDAS. 7*2 + 4 – 6 – 3 Multiply

Step 4: PEMDAS Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 4: Evaluate the expression, using PEMDAS. 14 + 4 – 6 – 3

Step 4: PEMDAS Order of Operations Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 4: Evaluate the expression, using PEMDAS. 14 + 4 – 6 – 3 No D left, so now simply Add and Subtract!

Step 5: PEMDAS The answer is 9 Order of Operations Expression: Practice Problem #1: Evaluate algebraic expression given variable values Expression: 7x + (12÷y)2 – y – (x+1) Given: x = 2 and y = 6 Step 5: Evaluate the expression, using PEMDAS. 18– 6 – 3  12 – 3  9 The answer is 9

Today’s Agenda 6/15/11 Review PEMDAS Example Problem Show common calculation errors Practice problems End-of-class assignment

Remember M and D are together A and S are together Following PEMDAS Solve from left to right

Example Expression WRONG! RIGHT! Common Mistakes Example Expression WRONG! RIGHT! Example #1 5 – 3 + 6 5 – 9 2 + 6 Example #2 10 – 8/2 2/2 10 – 4 Example #3 3 + 5(10 – 6) 8(10 – 6) 3 + 5(4)

Today’s Agenda 6/15/11 Review PEMDAS Example Problem Show common calculation errors Practice problems End-of-class assignment

Further Practice Example #1: when m = 2 and n = 3 3m – (n + 1) 3*2 – (3 + 1) 3*2 – (4) 6 – 4 2

Further Practice Example #2: when q = 1 and r = 2 (4q – r)2 – 1 (4*1 – 2)2 – 1 (4 – 2)2 – 1 22 – 1 4 – 1 3

Any questions about the last two problems?

Today’s Agenda 6/15/11 Review PEMDAS Example Problem Show common calculation errors Practice problems End-of-class assignment