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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?. Purpose.
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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?
Purpose • 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
PROBLEM 30 – 7 x 3 = ? Let’s look at a simple problem: Did you get 69 or maybe 9? Who is correct?
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.
ORDER OF OPERATIONS Pemdas Please Excuse My Dear Aunt Sally
Order of operations It’s easy to make a mistake, be sure to follow the rules. P Parenthesis E Exponents M Multiplications D Division A Addition S Subtraction As it appears, LEFT TO RIGHT
These are the simple 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.
Which student is correct? Student 1 4+5x2 = 9x2 = 18 Student 2 4+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.S 15 + 12 ÷ 3 - 5 Parentheses? NO! Exponents? Multiplication and/or division??? YES!!!! Do that first in this problem!!! 15 + (12 ÷ 3) - 5 15 + 4 - 5 Addition and/or subtraction? YES!!!! Do the addition left to right as it appears in the problem. 15 + 4 - 5 19 - 5= 14!!!
ON YOUR OWN Name the operation you should do first • 6 + 27 ÷ 3 • 5 x 2 + 12 ÷ 6 • 17 – (4 + 3) • (14 – 7) + (3 + 5 )
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! • 6 + 27 ÷ 3 • 5 x 2 + 12 ÷ 6 • 17 – (4 + 3) • (14 – 7) + (3 + 5 )
online • https://www.youtube.com/watch?v=CKLh2ksYBcY&feature=share • Brain Pop! • http://www.brainpop.com/math/numbersandoperations/orderofoperations/preview.weml