Unit 3 - Mathematics for Retail Sales Clerk


In mathematics, a percentage is a number or ratio that can be expressed as a fraction of 100. If we have to calculate percent of a number, divide the number by the whole and multiply by 100. Hence, the percentage means, a part per hundred. The word per cent means per 100. It is represented by the symbol “%”.

Question: "What is 50% of 25?"

Solution: Multiply the percentage by the whole

Equation: 0.50 x 25 = 12.5


In Trinidad and Tobago, VAT is 15%.

To calculate 15 percent of a number, you can multiply the number by 0.15 (which is the decimal equivalent of 15%). The result will be 15% of the original number.

For example, if the number is 50, then:

part = 0.15 × 50 = 7.5

So, 15% of 50 is 7.5.


How to calculate discount and sale price

Determine the original price (for example, $90 ).

Determine the discount percentage (for example, 20% ).

Calculate the savings: 20% of $90 = $18.

Subtract the savings from the original price to get the sale price: $90 - $18 = $72.

You've just applied the discount!