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Don’t Break the Laws of Math!

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Presentation on theme: "Don’t Break the Laws of Math!"— Presentation transcript:

1 Don’t Break the Laws of Math!
Learn the Order of Operations

2 Why? Why do we need an order of operations?
Consider the following problem:

3 There are two ways to solve this!
The order of operations tells us which way is correct. We even have a good way to remember the order of operations (next…)

4 Judge Judy Please Excuse My dear Aunt Sally

5 Do this first! ‘Please’ stands for parentheses and other grouping symbols. Parentheses ( ) Brackets [ ] Braces { } The fraction bar (groups the problem into a top and a bottom)

6 Then do these ‘Excuse’ stands for exponents.
Exponents are a shorthand for repeated multiplication of a number by itself.

7 Next come this pair ‘My Dear’ stands for: Multiply and divide IN ORDER
from left to right. Multiply is not more important – do whichever comes first as you go from left to right.

8 Last but not least! ‘Aunt Sally’ stands for: Add and subtract IN ORDER
from left to right.

9 Let’s try it! Please excuse my dear Aunt Sally
Since parentheses come first, it seems as if we should do something with the 5. But what? Trick #1 Parentheses can be used 2 different ways As a grouping symbol (that’s what Please means) As a multiplication sign (that’s what this is) How can you tell which way it’s being used? (next…)

10 Parentheses as a grouping symbol
If the parentheses are being used as a grouping symbol, there will be some action going on inside. By action, I mean Addition ( 5 + 4) Subtraction ( 7 – 3) Multiplication ( 6 x 4 ) Division ( 10 / 2 )

11 Parentheses as a multiplication symbol
Once we start algebra and use x to mean the unknown number that we’re trying to find, we can’t also use x to mean multiply. One way to indicate multiplication is with a number followed immediately by parentheses. 5 ( ) means 5 times whatever is inside the parentheses 2 of the most popular alternate multiplication signs are parentheses 4 ( 5 ) and a raised dot

12 S M A M Identify your operations and them perform them in the correct order. Multiply first – from left to right. Then add and subtract in order.

13 A D M E Identify your operations and them perform them in the correct order. Exponents first, then multiply and divide, in order, from left to right. Add last.

14 D P M P Identify your operations and them perform them in the correct order. Parentheses first, then multiply and divide, in order, from left to right. The parentheses around the 5 in line 2 are optional.

15 M A M Identify your operations and them perform them in the correct order. Multiply first and then add.

16 P E D M Identify your operations and them perform them in the correct order. Parentheses first, then exponents, then multiply and divide in order.

17 Order is important in court . . and in math!
Please excuse my dear Aunt Sally.


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