Order of Operations Module I, Lesson 1 Online Algebra

36 – [(4x 5) – 6] x 2  Simplify the above expression.  What did you get?  With all those numbers how do we know what order to compute?  We need a set of rules to follow so everyone gets the same answer.

Order of Operations The steps that we follow to simplify expressions are called Order of Operations. The rules that we follow are: 1. Grouping Symbols  Parentheses, brackets and fraction bars 2. Exponents 3. Multiplication and division, what ever comes first from left to right. 4. Addition and subtraction, what ever comes first from left to right.

PEMDAS You might have learned this as PEMDAS or Please Excuse My Dear Aunt Sally. P for Parentheses E for Exponents M for Multiplication D for Division A for Addition S for Subtraction This is a great way to remember this as long as you remember that: 1.There is more to grouping symbols then parentheses 2. Do multiplication and division as what ever comes first 3.Do addition and subtraction whichever comes first

36 – [(4x 5) – 6] x 2 So how do simplify the above expression correctly? 1. Do whatever is in grouping symbols first. If there is more than one set, do the inner most first. 2. We still have operations in grouping symbols so we need to do that. 3. There are no exponents so we need to do any multiplication and division. 4. Lastly we do addition and/or subtraction 36 – [20 – 6] x 2 36 – 14 x 2 36 – 28 8 Notice that there is one step per line and that all work is shown!

Let’s try another. 10 2(4 – 3) 1. In this case the fraction bar is the grouping symbol. We need to do everything above and everything below, following order of operations. 2. Since the numerator is already simplified we need to just simplify the denominator. 3. Lastly, a fraction is just another way to write division, so we divide. 10 2(4 – 3) 10 2(1)

Try these! Click to check your answer! (2 + 3) 2 – – – (9) (81) – – Remember to grouping symbols before exponents! Remember to do exponents before multiplication!

Order Of Operations Don’t forget to follow the following steps when simplifying expressions! 1. Grouping Symbols  Parentheses, brackets and fraction bars 2. Exponents 3. Multiplication and division, what ever comes first from left to right. 4. Addition and subtraction, what ever comes first from left to right.

Homework Worksheet 1.1 The worksheet can be found on the assignments page in the Chapter 1 homework folder