Syllabus Dot-Point(s)

• Calculate simple interest using the formula I=PRN where I is the interest, P is the principal, R is the interest rate per time period (expressed as a fraction or decimal) and N is the number of time periods
  • Apply the simple interest formula to solve problems related to investing money at simple interest rates

Lesson Goal

By the end of this lesson, students will apply the formula, I=PRN, to calculate simple interest.

• MA5.1-2WM Selects and uses appropriate strategies to solve problems
• MA5.1-4NA Solves financial problems involving earning, spending and investing money

Outcomes

• MA5.1-1WM Uses appropriate terminology, diagrams and symbols in mathematical contexts
• MA5.1-2WM Selects and uses appropriate strategies to solve problems
• MA5.1-4NA Solves financial problems involving earning, spending and investing money

Working mathematically

• Find the total value of a simple interest investment after a given time period (Problem Solving)
• Calculate the principal or time needed to earn a particular amount of interest, given the simple interest rate (Problem Solving)

Class

Stage: 5.1

Ability: Mixed

Duration: 50 minutes

Introduction

10 mins

• Recap: Ask if students have any questions from homework assigned in the previous lesson. Quickly address any misconceptions. Explain and demonstrate working-out on the whiteboard. Students copy this into their exercise books.
• Ask how students are progressing with the $5 challenge. Some or all students can quickly share this with the class.
• Distribute Exit Slip to students
• Briefly explain what will be learned during this lesson.
• Teacher introduces a new concept using google presentation slides

Activity

15 mins

• Teacher guides students to figure out the formula for simple interest, I=PRN. Teacher can explain/demonstrate a few related examples from their preferred textbook.
• Then, teacher uses resource below:

• If extra practice questions are needed, students can play this online quiz for simple interest.

Additional Teacher Resources

• Khan Academy - Simple Interest Word Problems
• Math is Fun - Introduction to Simple Interest

Activity

20 mins

Students play an online game for calculating simple interest called Simple Interest Rates Battleship by Quia.

Conclusion

5 mins

• Homework: assign related exercises in your preferred textbook. Remind students to label questions they have trouble with for clarification at the beginning of the next lesson.
• Briefly explain the relationship between this and the following lesson
• Students return completed Exit Slip (AFL)
• Students show completed homework from previous lesson

Educators are encouraged to keep a teacher’s journals for the following critical reflections, based on class observations and feedback from exit slips:

What went well, and why?

Did students understand the concepts?

Were students engaged?

What improvements can be made, and how?

Which students may require extra support, and how?

Which students may require more challenging content?

Are there additional resources that can be added to this lesson?