Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Calculate simple interest.
• Calculate the impact of inflation on prices.
• Construct a personal or family budget.
• Analyse how inflation affects a budget.
• Make informed decisions about savings and loans.

Lesson summary

This week, we delve into the crucial financial concepts of simple interest, inflation, and budgeting. Understanding these concepts is not just an academic exercise; it is vital for making informed financial decisions throughout your life in South Africa. From saving for tertiary education or a car to understanding the impact of rising prices on your family's budget, these skills will empower you to take control of your financial future. Many South Africans struggle with debt and financial insecurity due to a lack of financial literacy. This topic aims to equip you with the tools to avoid these pitfalls and build a stable financial foundation.

Lesson notes

Simple Interest Simple interest is a straightforward way of calculating interest on a principal amount. It's calculated only on the original principal and not on any accumulated interest.

The formula for simple interest is: I = P x r x t Where: I = Interest earned or paid P = Principal amount (the initial amount invested or borrowed) r = Interest rate (expressed as a decimal, e.g., 10% = 0.10) t = Time period (usually in years)

Example 1: Zinhle invests R5,000 in a fixed deposit account that pays a simple interest rate of 8% per annum (per year). She invests the money for 3 years. How much interest will she earn? What will be the total value of her investment after 3 years?

Solution: P = R5,000 r = 8% = 0.08 t = 3 years I = P x r x t = R5,000 x 0.08 x 3 = R1,200 Therefore, Zinhle will earn R1,200 in interest. The total value of her investment after 3 years will be the principal plus the interest: Total Value = P + I = R5,000 + R1,200 = R6,200 Example 2: Sipho borrows R10,000 from a loan shark. The loan shark charges a simple interest rate of 20% per year. Sipho plans to repay the loan in 6 months (0.5 years). How much interest will Sipho pay? What is the total amount Sipho needs to repay?

Solution: P = R10,000 r = 20% = 0.20 t = 6 months = 0.5 years I = P x r x t = R10,000 x 0.20 x 0.5 = R1,000 Therefore, Sipho will pay R1,000 in interest.

The total amount Sipho needs to repay is: Total Amount = P + I = R10,000 + R1,000 = R11,000 Important

Note: Be very wary of high interest rates, like the one in Example

2. These are often charged by unscrupulous lenders and can lead to a debt trap. Always compare interest rates from different lenders before taking out a loan. Inflation Inflation is the rate at which the general level of prices for goods and services is rising, and subsequently, purchasing power is falling. In simple terms, it means that your money buys less than it used to. Inflation is usually expressed as a percentage per year.

Calculating the Future Price of an Item: To calculate the future price of an item after inflation, we can use the following formula (an adaptation of the simple interest formula where the inflation rate acts as the interest rate and the initial price as the principal): Future Price = Present Price x (1 + Inflation Rate)^Number of Years Example 3: A loaf of bread currently costs R

1

5. If the inflation rate is 6% per year, what will the price of the same loaf of bread be in 2 years?

Solution: Present Price = R15 Inflation Rate = 6% = 0.06 Number of Years = 2 Future Price = R15 x (1 + 0.06)^2 = R15 x (1.06)^2 = R15 x 1.1236 = R16.85 (rounded to the nearest cent) Therefore, the price of the loaf of bread will be approximately R16.85 in 2 years.

Example 4: A textbook currently costs R

2

5

0. If the inflation rate is expected to be 5% per year, what will the price of the textbook be in 5 years?

Solution: Present Price = R250 Inflation Rate = 5% = 0.05 Number of Years = 5 Future Price = R250 x (1 + 0.05)^5 = R250 x (1.05)^5 = R250 x 1.27628 = R319.07 (rounded to the nearest cent) Therefore, the price of the textbook will be approximately R319.07 in 5 years. This shows how important it is to start saving early for future expenses, considering inflation. Budgeting A budget is a plan for managing your income and expenses. It helps you track where your money is going and ensures that you are spending within your means. A good budget will help you to achieve your financial goals, such as saving for a car, a house, or education.

Steps to Creating a Budget: Calculate your income: This includes all sources of income, such as salary, wages, allowances, and any other money you receive.

List your expenses: This includes all your regular expenses, such as rent/bond payments, transportation, food, clothing, entertainment, and utilities (electricity, water, etc.). Distinguish between fixed expenses (those that stay relatively the same each month) and variable expenses (those that change).

Subtract your expenses from your income: This will give you your net income or cash flow. If your expenses are higher than your income, you have a deficit, and you need to find ways to reduce your expenses or increase your income.

Review and adjust your budget regularly: Your budget should be a living document that you update regularly to reflect changes in your income and expenses.

Example 5: Thabo earns R4,000 per month from his part-time job.

His monthly expenses are: Rent: R1,500 Transportation: R500 Food: R1,000 Entertainment: R500 Clothing: R300 Miscellaneous: R200 Create a budget for Thabo.

Solution: Thabo's Monthly Budget: Income: R4,000 Expenses: Rent: R1,500 Transportation: R500 Food: R1,000 Entertainment: R500 Clothing: R300 Miscellaneous: R200 Total Expenses: R4,000 Net Income: R4,000 (Income) - R4,000 (Expenses) = R0 In this case, Thabo is breaking even. He needs to either increase his income or decrease his expenses to have some money left over for savings or unexpected costs.