Order of Operation TEKS 6.2E Lesson 6 (2nd 6 Weeks)

Order of Operations The order in which operations are computed in an expression.

To Simplify an Expression Follow this order of operations: STEP 1: Simplify any operations in parentheses and brackets. If there is more than one operation within a set of parentheses, follow the order of operations in steps 2, and 3.

STEP 2: Calculate all multiplication and division from left to right. STEP 3: Calculate all addition and subtraction from left to right.

A phrase that is helpful in remembering the order of operations is: “Please Excuse My Dear Aunt Sally”

Please (Parentheses, first) Excuse (Exponents-we don’t do) My Dear (Multiply and Divide from Left to Right) Aunt Sally (Add and Subtract from Left to Right)

Remember: Multiplication is not always done before division Remember: Multiplication is not always done before division. Work left to right. Whichever one comes first, is done first. Same for addition and subtraction.

Order Of Operations Method 2 Method 1 Performing operations using order of operations Performing operations left to right only Can you imagine what it would be like if calculations were performed differently by various financial institutions or what if doctors prescribed different doses of medicine using the same formulas and achieving different results? The rules for order of operations exist so that everyone can perform the same consistent operations and achieve the same results. Method 2 is the correct method.

Simplify the Expression 12÷3+4·6-2·3 1. There are no parentheses 2. Multiply and divide from left to right. 12÷3+4·6-2·3 4 + 24 - 6

3. Add and subtract from left to right. 4+24-6 28-6 22 4. The expression simplifies to 22.

Are you up to the challenge? A good rule of thumb is to underline the part of the expression that you are doing first. 1. (8+3)-5 -5 6 11

2. 24 - (19 - 19) 24 – 24

3. 5 x 8 - 3 x 4 40 -12 28

4. 3 + 5 · 4 3 + 20 23

5. (24 - 10) - 3 · 3 14 – 3 · 3 14- 9 5

6. 4(22-18÷3) · 5 4(22- )· 5 6 4· · 5 16 64 ·5 320

7. 3(18 - 12) - (5 - 3) 3 x - 6 2 18 - 2 16

If a = 5 and b = 4, solve 5a – 3b 5 x – 3 x a 5 b 4 25 - 12 13

A family of five is going to the zoo A family of five is going to the zoo. Adult tickets are $7 each and children’s tickets are $5 each.

Write an equation to find c, the total cost of going to the zoo if you buy two adult and three children’s tickets.

Solve the equation you wrote. (2 x 7) + (3 x 5) = c

(2 x 7) + (3 x 5) = c 14 + = c 15 $ 29 = c