Commercial Arithmetic - JSS2 Mathematics Lesson Note

Commercial arithmetic is used in business and commerce, including tasks like calculating profit, interest, discounts, and taxes. Here are a few examples:

Example 1: Calculating Profit

A store buys a product for $50 and sells it for $80. To find the profit:

Calculations:

Profit=Selling Price−Cost Price=80−50=30

The profit is $30.

Example 2: Calculating Interest

If you deposit $1,000 in a savings account with an annual interest rate of 5%, the interest earned in one year is calculated as follows:

Calculations:

Interest=Principal× Rate× Time=1000×0.05×1=50

You will earn $50 in interest after one year.

Example 3: Calculating Discounts

A store offers a 20% discount on an item that costs $100.

Calculations:

Discount:=Original Price× Discount Rate/100 

=100×20/100= 20

Sale Price=Original Price−Discount=100−20=80

The item costs $80 after the discount.

Example 4: Calculating Taxes

If an item costs $200 and the sales tax rate is 8%, the total cost including tax is:

Calculations:

Tax:=Cost× Tax Rate/100

=200×8/100

=16

Total Cost=Cost+ Tax=200+16=216

The total cost including tax is $216.