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TEKS 6.2E

Lesson 6 (2nd 6 Weeks)

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• The order in which operations are computed in an expression.

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• 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.

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• STEP 2: Calculate all multiplication and division from left to right.

• STEP 3: Calculate all addition and subtraction from left to right.

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

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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)

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

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53621 53621 53621

5327

5945

53621 5221 5221

102131

5327

Performing operations left to right only

Performing operations using order of operations

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.

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.

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?

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?

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Simplify the Expression12÷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+ -

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3. Add and subtract from left to right.

4+24-6

28-6

22

4. The expression simplifies to 22.

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1. (8+3)-5 -5

6

11

A good rule of thumb is to

underline the part of the

expression that you are doing

first.

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2. 24 - (19 - 19) 24 –

240

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3. 5 x 8 - 3 x 4

28

-1240

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4. 3 + 5 · 4

23

3 +20

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5. (24 - 10) - 3 · 3

5

– 3 · 314-

149

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6. 4(22-18÷3) · 5

64

4(22- )· 5

·5

616 4· · 5

320

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7. 3(18 - 12) - (5 - 3)

16

3 x -

- 2

6

18

2

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If a = 5 and b = 4, solve 5a – 3b

13

5 x – 3 x -25 12

a b5 4

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

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

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Solve the equation you wrote.

(2 x 7) + (3 x 5) = c

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(2 x 7) + (3 x 5) = c

+ = c

$ 29 = c

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