2.2.1.5 - Order of Operations (PEMDAS/BODMAS)

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Interactive Audio Lesson

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Introduction to PEMDAS and BODMAS

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Teacher
Teacher

Today, we'll learn about the Order of Operations, which is crucial for solving mathematical expressions accurately. Can anyone tell me what they think we should do first when we see a complex expression?

Student 1
Student 1

I think we should solve the numbers inside parentheses first.

Teacher
Teacher

Exactly! The first step is to solve what's in Parentheses or Brackets. Thatโ€™s the 'P' in PEMDAS and the 'B' in BODMAS. What comes next?

Student 2
Student 2

Exponents or orders, right?

Teacher
Teacher

Correct! After addressing the parentheses, we tackle Exponents. Can someone give me an example of an exponent?

Student 3
Student 3

Like 2 squared, which is 4?

Teacher
Teacher

Exactly! Now, after exponents, we proceed with Multiplication and Division from left to right. And finally, Addition and Subtraction. Remember, both multiplication and division come before addition and subtraction.

Student 4
Student 4

So, we can do them in the order we see from left to right?

Teacher
Teacher

Yes! Letโ€™s summarize: First Parentheses, then Exponents, followed by Multiplication and Division, and finally Addition and Subtraction. That's PEMDAS/BODMAS!

Applying the Order of Operations

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Teacher
Teacher

Letโ€™s apply these rules! Solve the expression: 3 + 6 ร— (5 + 4) รท 3. Whatโ€™s the first step?

Student 1
Student 1

We solve the parentheses first, so 5 + 4 equals 9.

Teacher
Teacher

Great! Now the expression is 3 + 6 ร— 9 รท 3. What next?

Student 2
Student 2

We do multiplication and division from left to right. So, 6 ร— 9 is 54.

Teacher
Teacher

Exactly! What do we have now?

Student 3
Student 3

54 รท 3, which is 18.

Teacher
Teacher

So, now we have 3 + 18 left to solve. Finally?

Student 4
Student 4

That would be 21!

Teacher
Teacher

Perfect! By following the Order of Operations, we arrived at the correct answer.

Common Mistakes in Order of Operations

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Teacher
Teacher

Now that we understand how to apply PEMDAS/BODMAS, letโ€™s talk about common mistakes. Why might students get the wrong answer even if they know the order?

Student 1
Student 1

Maybe they forget to do multiplication before addition?

Teacher
Teacher

Yes! Thatโ€™s a frequent mistake. Just to be clear, performing addition before multiplication or division can lead to incorrect results. Letโ€™s look at an example. Whatโ€™s wrong with the expression: 2 + 3 ร— 4?

Student 2
Student 2

If someone adds first, theyโ€™d say 5 and then multiply by 4, which gives 20 instead of the right answer.

Teacher
Teacher

Exactly! The correct way is to multiply first, getting 3 ร— 4 equals 12, then add 2 for a total of 14. Remember, always follow PEMDAS/BODMAS to avoid these errors!

Introduction & Overview

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Quick Overview

The Order of Operations is a set of rules that dictates the correct sequence to evaluate mathematical expressions.

Standard

Understanding the Order of Operations (PEMDAS/BODMAS) helps students accurately solve mathematical expressions by knowing which operations to perform first. This includes evaluating Parentheses/Brackets, Exponents/Orders, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right).

Detailed

In mathematics, expressions can become complex with multiple operations like addition, subtraction, multiplication, division, and more. To ensure everyone arrives at the same solution, mathematicians created a standard Order of Operations. This acronym is known as PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction) in the United States. In some countries, it is referred to as BODMAS (Brackets, Orders, Division and Multiplication, Addition and Subtraction). This section provides an overview of these rules, emphasizing their importance in evaluating expressions correctly. By following PEMDAS/BODMAS, students can avoid common errors and misunderstandings in mathematical computations.

Definitions & Key Concepts

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Key Concepts

  • PEMDAS: The order of operations used mainly in the US.

  • BODMAS: The order of operations used in some other countries.

  • Parentheses/Brackets: Indicates which operations should be performed first.

  • Exponents: Powers that indicate how many times to multiply a number by itself.

  • Multiplication and Division: Operations performed from left to right next.

  • Addition and Subtraction: The final operations performed from left to right.

Examples & Real-Life Applications

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Examples

  • Example 1: For the expression 2 + (3 ร— 4), solve the parentheses first: 2 + 12 = 14.

  • Example 2: For 8 รท 4 + 2, first divide: 2 + 2 = 4.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

๐ŸŽต Rhymes Time

  • Please Excuse My Dear Aunt Sally, that's how you remember PEMDAS!

๐Ÿ“– Fascinating Stories

  • Once upon a time, a math wizard could never remember the order of operations, until a wise owl taught him PEMDAS, saving the kingdom from calculation chaos.

๐Ÿง  Other Memory Gems

  • P-E-M-D-A-S: Parentheses must come first, then Exponents explode, and Multiplication and Division march from left to right, followed by Addition and Subtraction settling at the end.

๐ŸŽฏ Super Acronyms

To remember BODMAS, just think

  • Brackets first
  • Orders next
  • Division and Multiplication next
  • and finally Addition and Subtraction.

Flash Cards

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Glossary of Terms

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  • Term: PEMDAS

    Definition:

    An acronym representing the Order of Operations: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).

  • Term: BODMAS

    Definition:

    An alternative acronym representing Order of Operations common in some countries: Brackets, Orders, Division and Multiplication (from left to right), Addition and Subtraction (from left to right).

  • Term: Order of Operations

    Definition:

    A set of rules specifying the order in which calculations should be performed.