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

Sign the check Check the sign 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. Oh no! Ex. 3 + 5 X 2 What do we do first? Add or multiply? If we add first: If we multiply first: 3 + 5 X 2 3 + 5 X 2 8 X 2 3 + 10 Help! 16 13 Uh Oh! Which one is the correct answer?

Have no fear! PEMDAS is here!

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 23 Whichever comes first from left to right! Multiplication X Division ÷ Addition + Whichever comes first from left to right! Subtraction -

How am I supposed to remember that! Please Excuse My Dear Aunt Sally

Part 1 Using the Order of Operations PEMDAS What do we do first? 3 + 5 X 2 Multiply first 3 + 10 Then add 13

To simplify an expression means to replace the expression with the simplest name for its value. PEMDAS Example 1: Simplify 4 + 15 ÷ 3 4 + 15 ÷ 3 Divide first 4 + 5 Then add 9

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

When operations have the same rank in the order of operations, do them from left to right. PEMDAS Example 2 . Simplify 3 5 – 8 ÷ 4 + 6 multiply & divide from left to right . 3 5 – 8 ÷ 4 + 6 add and subtract from left to right - 15 2 + 6 13 + 6 19

. . Try This! Simplify each expression 4) 4 – 1 2 + 6 ÷ 3 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)]. PEMDAS . 10 ÷ [9 – (2 2)] Multiply in parenthesis. 10 ÷ [9 – ] 4 Subtract in brackets. 10 ÷ 5 Divide. 2