# 1-2 The Order of Operations Objective: Use the order of operations and grouping symbols.

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1-2 The Order of Operations Objective: Use the order of operations and grouping symbols.

In most languages, the meaning of words depend on the order: Ex. Sign the check Is not the same as Check the sign

Mathematics is a type of language and it also has a specific order. Ex. 3 + 5 X 2 What do we do first? Add or multiply? If we add first: 3 + 5 X 2 8X 2 16 If we multiply first: 3 + 5 X 2 103 + 13 Uh Oh! Which one is the correct answer? Help ! Oh no!

What is PEMDAS? In order to make sure every person gets the same answer to a math problem, mathematicians came up with a rule called the order of operations Parenthesis ( ) [ ] Exponents 2 3 Multiplication X Division ÷ Addition + Subtraction - Whichever comes first from left to right!

How am I supposed to remember that! P l e a s e E x c u s e M y D e a r A u n t S a l l y

Part 1 Using the Order of Operations 3 + 5 X 2 What do we do first? PEMDA S 103 + 13 Multiply first Then add

To simplify an expression means to replace the expression with the simplest name for its value. Example 1: Simplify 4 + 15 ÷ 3 4 + 15 ÷ 3 PEMDAS 54 + 9 Divide first Then add

Now you try! 1) 2 + 5 X 3 2) 12 ÷ 3 - 1 3) 10 – 1 7. Simplify each expression.

When operations have the same rank in the order of operations, do them from left to right. Example 2 Simplify 3 5 – 8 ÷ 4 + 6. PEMDAS 3 5 – 8 ÷ 4 + 6. multiply & divide from left to right 152 - +6 13+6 19 add and subtract from left to right

Try This! Simplify each expression 4) 4 – 1 2 + 6 ÷ 3. 5) 5 + 6 4 ÷ 3 - 1.

Part 2 Using grouping Symbols Grouping symbols such as parenthesis ( ) and brackets [ ] come first in the order of operations. A fraction bar is also a grouping symbol since: 4 + 2 = (4 + 2) ÷ 3 3 Always work inside grouping symbols first!

Order of Operations 1) Work inside grouping symbols. 2) Multiply and divide from left to right. 3) Add and subtract in order from left to right.

Example 3 Simplify 10 ÷ [9 – (2 2)].. 10 ÷ [9 – (2 2)]. 10 ÷ [9 – ] 10 ÷ 4 5 2 Multiply in parenthesis. Subtract in brackets. Divide. PEMDAS

You Try! 9) 2[ (13 – 4) ÷ 3] 10) 1 + 10 - 2 4

Let’s do math! Classwork: pg. 11 #’s 1-9 odd Homework: pg. 11 #’s 10 – 34 even

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