Learn on PengiOpenstax Prealgebre 2EChapter 9: Math Models and Geometry

Lesson 1: Use a Problem Solving Strategy

In this lesson from OpenStax Prealgebra 2E, Chapter 9, students learn how to apply a structured problem-solving strategy to translate word problems into algebraic equations and solve them. The lesson covers approaching word problems with a positive mindset, identifying variables, and working through number problems step by step. It serves as the foundation for the geometry and math modeling topics explored throughout the rest of the chapter.

Section 1

πŸ“˜ Use a Problem Solving Strategy

New Concept

Learn a systematic, 7-step strategy to confidently translate any word problem into a solvable equation. This approach builds skills for tackling various number problems by breaking them down into manageable parts, turning challenges into clear solutions.

What’s next

Next, we'll walk through this 7-step strategy with interactive examples. Then, you'll apply it yourself in a series of practice problems.

Section 2

Approach word problems with a positive attitude

Property

Start with a fresh slate and begin to think positive thoughts. If we take control and believe we can be successful, we will be able to master word problems. Word problems are a learnable skill, just like driving a car or cooking a meal.

Examples

  • Instead of thinking 'I'll never get this,' try thinking 'I can read the problem carefully and identify what it's asking.'
  • Instead of saying 'I'm bad at word problems,' remind yourself 'I have learned many new math skills that will help me succeed now.'

Section 3

Problem-solving strategy for word problems

Property

  1. Read the word problem to understand all the words and ideas.
  2. Identify what you are looking for.
  3. Name what you are looking for by choosing a variable.
  4. Translate the words into an algebraic equation.
  5. Solve the equation using good algebra techniques.
  6. Check the answer to make sure it makes sense in the context of the problem.
  7. Answer the question with a complete sentence.

Examples

  • A hat is on sale for 15 dollars, which is one-third the original price. What was the original price? Let pp be the original price. The equation is 15=13p15 = \frac{1}{3}p. Multiply by 3 to get p=45p = 45. The original price was 45 dollars.
  • The number of oranges was 4 more than twice the number of lemons. If there were 16 oranges, how many lemons were there? Let LL be the number of lemons. The equation is 16=2L+416 = 2L + 4. Solving gives 12=2L12 = 2L, so L=6L=6. There were 6 lemons.

Section 4

Solve number problems

Property

In number problems, you are given clues about one or more numbers and you use these clues to build an equation. When a problem involves two or more numbers, define them in terms of the same variable.

Examples

  • The sum of a number and five is 18. Find the number. Let the number be nn. The equation is n+5=18n + 5 = 18. Subtracting 5 from both sides gives n=13n = 13. The number is 13.
  • The difference of three times a number and four is 11. Find the number. Let the number be xx. The equation is 3xβˆ’4=113x - 4 = 11. Adding 4 gives 3x=153x = 15, so x=5x=5. The number is 5.

Section 5

Consecutive integers

Property

Consecutive integers are integers that immediately follow each other. If we define the first integer as nn, the next consecutive integer is n+1n + 1. The one after that is one more than n+1n + 1, so it is n+1+1n + 1 + 1, or n+2n + 2.

nn = 1st integer

n+1n + 1 = 2nd consecutive integer

Book overview

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Chapter 9: Math Models and Geometry

  1. Lesson 1Current

    Lesson 1: Use a Problem Solving Strategy

  2. Lesson 2

    Lesson 2: Solve Money Applications

  3. Lesson 3

    Lesson 3: Use Properties of Angles, Triangles, and the Pythagorean Theorem

  4. Lesson 4

    Lesson 4: Use Properties of Rectangles, Triangles, and Trapezoids

  5. Lesson 5

    Lesson 5: Solve Geometry Applications: Circles and Irregular Figures

  6. Lesson 6

    Lesson 6: Solve Geometry Applications: Volume and Surface Area

  7. Lesson 7

    Lesson 7: Solve a Formula for a Specific Variable

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

πŸ“˜ Use a Problem Solving Strategy

New Concept

Learn a systematic, 7-step strategy to confidently translate any word problem into a solvable equation. This approach builds skills for tackling various number problems by breaking them down into manageable parts, turning challenges into clear solutions.

What’s next

Next, we'll walk through this 7-step strategy with interactive examples. Then, you'll apply it yourself in a series of practice problems.

Section 2

Approach word problems with a positive attitude

Property

Start with a fresh slate and begin to think positive thoughts. If we take control and believe we can be successful, we will be able to master word problems. Word problems are a learnable skill, just like driving a car or cooking a meal.

Examples

  • Instead of thinking 'I'll never get this,' try thinking 'I can read the problem carefully and identify what it's asking.'
  • Instead of saying 'I'm bad at word problems,' remind yourself 'I have learned many new math skills that will help me succeed now.'

Section 3

Problem-solving strategy for word problems

Property

  1. Read the word problem to understand all the words and ideas.
  2. Identify what you are looking for.
  3. Name what you are looking for by choosing a variable.
  4. Translate the words into an algebraic equation.
  5. Solve the equation using good algebra techniques.
  6. Check the answer to make sure it makes sense in the context of the problem.
  7. Answer the question with a complete sentence.

Examples

  • A hat is on sale for 15 dollars, which is one-third the original price. What was the original price? Let pp be the original price. The equation is 15=13p15 = \frac{1}{3}p. Multiply by 3 to get p=45p = 45. The original price was 45 dollars.
  • The number of oranges was 4 more than twice the number of lemons. If there were 16 oranges, how many lemons were there? Let LL be the number of lemons. The equation is 16=2L+416 = 2L + 4. Solving gives 12=2L12 = 2L, so L=6L=6. There were 6 lemons.

Section 4

Solve number problems

Property

In number problems, you are given clues about one or more numbers and you use these clues to build an equation. When a problem involves two or more numbers, define them in terms of the same variable.

Examples

  • The sum of a number and five is 18. Find the number. Let the number be nn. The equation is n+5=18n + 5 = 18. Subtracting 5 from both sides gives n=13n = 13. The number is 13.
  • The difference of three times a number and four is 11. Find the number. Let the number be xx. The equation is 3xβˆ’4=113x - 4 = 11. Adding 4 gives 3x=153x = 15, so x=5x=5. The number is 5.

Section 5

Consecutive integers

Property

Consecutive integers are integers that immediately follow each other. If we define the first integer as nn, the next consecutive integer is n+1n + 1. The one after that is one more than n+1n + 1, so it is n+1+1n + 1 + 1, or n+2n + 2.

nn = 1st integer

n+1n + 1 = 2nd consecutive integer

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 9: Math Models and Geometry

  1. Lesson 1Current

    Lesson 1: Use a Problem Solving Strategy

  2. Lesson 2

    Lesson 2: Solve Money Applications

  3. Lesson 3

    Lesson 3: Use Properties of Angles, Triangles, and the Pythagorean Theorem

  4. Lesson 4

    Lesson 4: Use Properties of Rectangles, Triangles, and Trapezoids

  5. Lesson 5

    Lesson 5: Solve Geometry Applications: Circles and Irregular Figures

  6. Lesson 6

    Lesson 6: Solve Geometry Applications: Volume and Surface Area

  7. Lesson 7

    Lesson 7: Solve a Formula for a Specific Variable