Lesson 1:

Order of Operations

Learning Objective/s

• State, explain, and interpret PMDAS or GMDAS rule

• Simplify a series of operations on whole numbers involving more than two operations using the PMDAS or GMDAS rule

Success Criteria

The learners are able to:

Understand and articulate of the PMDAS or GMDAS rule.

Simplify expressions involving more than two operations.

Discussions

Answer this.

Mother prepared 3 plates of pandesal, each plate with 12 pandesal. She will equally serve the pandesal among her 9 neighbors who will visit her. How many pandesal will each neighbor get?

Think and Understand

Can you tell who is thinking of the correct order of operations? How do you know?

When there is more than one operation (+, –, ×, ÷) in a mathematical expression, you must follow the correct order of operations. Otherwise, you may end up getting a different or incorrect answer.

Over the years, mathematicians established rules for the order of operations to avoid confusion on how a problem should be solved.

These rules are:

1. If there are expressions in parentheses or in grouping symbols such as brackets [ ], ( ), { }, do them first.

2. Next, multiply or divide from left to right.

3. Finally, add or subtract from left to right.

Put together the beginning letters of parentheses (or group), multiply, divide, add, subtract, and you will have PMDAS or GMDAS to remember the rules of the order of operations.

Check your Understanding

Read and answer each.

1. Simplify this expression: (6 × 7) + 40 ÷ 8 – 2. Explain in detail or step by step, why the answer is 45.

2. How will you simplify an expression that has two operations, addition and subtraction?

3. How will you simplify an expression that has two operations, multiplication and division?

4. Explain how you will solve this problem: What number will result if you subtract 4 from 20 and then divide the difference by 8?

Practice

Complete the following to make true statements.

1. 37 + 36 ÷ 9 = _____

2. 25 – 16 + 8 = _____

3. _____ = 6 × 7 – 5

4. 9 × 2 + 13 – 8 = _____

Cross Curricular Link

Physical Fitness - Create mathematical equations that involve the order of operations for each station.

For example:

Station 1 (Addition): Perform 10 jumping jacks + 5 squats.
Station 2 (Multiplication): Do 15 push-ups × 2.
Station 3 (Subtraction): Complete 20 lunges - 8.

Real Life - Application

It helps determine the sequence in which expenses such as material costs, labor fees, and taxes should be calculated, ensuring an accurate and well-organized financial plan.

Evaluation