Let’s look at a simple problem:

Let’s look at a simple problem:

30 – 7 x 3 = ?

Can everyone here subtract and multiply?

Let’s work it out now and see what we get?

• You already know how to add, subtract, multiply, and divide. Today you will learn how to evaluate a numerical expression with more than one operation.

• Have you ever followed the directions in a recipe? What do you think would happen if you changed the order of the directions?

Connect

Purpose

Let’s look at a simple problem:

Did you get 69 or maybe 9?

Who is correct?

PROBLEM

30 – 7 x 3 = ?

A very long time ago, Mathematicians were dealing with this same problem.

Mathematicians were solving these type of problems and were coming up with different answers.

They decided to make some rules that we all need to follow to make sure that we all get the same answer.

Rules for the Order of Operations

This is what they came up

with.We know it as PEMDAS

Vocabulary• When evaluating expressions containing

more than one operation, you need to use the order of operations. The order of operations states that operations in parentheses are evaluated first, followed by multiplication and division from left to right. Finally, addition and subtraction are completed from left to right.

Please Excuse My Dear Aunt Sally Pemdas

P Parenthesis

E Exponents

M MultiplicationsD Division

A AdditionS Subtraction

As it appears, LEFT TO RIGHT

Order of operationsIt’s easy to make

a mistake, be sure to follow the

rules.

Rule 1: First perform any calculations inside parentheses. (if working with exponents, those come next) Rule 2: Next perform all multiplications and divisions, working from left to right. Rule 3: Lastly, perform all additions and subtractions, working from left to right.

These are the simple

rules

Which student is correct?

Student 14+5x2= 9x2= 18

Student 24+5x 2= 4+10= 14

15 + 12 ÷ 3 - 5• When you evaluate an expression, what

operation do you do first?

• Are there any parentheses in this expression?

• What do you do if there are no parentheses?

First, you do whatever operations are in parentheses

P.E.M.D.A.S15 + 12 ÷ 3 - 5

15 + (12 ÷ 3) - 5

Parentheses? NO! Exponents?

Multiplication and/or division???

YES!!!! Do that first in this problem!!!

15 + 4 - 5Addition and/or subtraction?

YES!!!! Do the addition left to right as it appears in the problem.

15 + 4 - 519 - 5= 14!!!

Name the operation you should do first1. 6 + 27 ÷ 32. 5 x 2 + 12 ÷ 63. 17 – (4 + 3)4. (14 – 7) + (3 + 5 )

ON YOUR OWN

On your own• Place the parentheses that would make this

equation true.

12 + 14 – 4 ÷ 2 = 17 (pay attention to the answer!!!!)

Now let’s solve these!

1. 6 + 27 ÷ 32. 5 x 2 + 12 ÷ 63. 17 – (4 + 3)4. (14 – 7) + (3 + 5 )

online• https://www.youtube.com/watch?

v=CKLh2ksYBcY&feature=share

• Brain Pop!• http://www.brainpop.com/math/numbersando

perations/orderofoperations/preview.weml