Today we’re going to learn about percentages. A percentage is a way of expressing a number as a fraction of 100. It’s denoted by the symbol “%”. Understanding percentages is very important in daily life – from calculating sales tax to determining grades. So let’s dive in!
What is a Percentage?
Simply put, the word “percent” means “per hundred.” So, when we talk about percentages, we are describing how many parts out of 100 we have.
Basic Percentage Formula
The basic formula to calculate the percentage of a number is:
Percentage (%) = (Value / Total Value) × 100
Examples:
- If you have 20 apples out of a total of 100 apples, what is the percentage of apples you have?
- Solution: (20 / 100) × 100 = 20%
- If you scored 45 marks out of 50 in a test, what percentage did you get?
- Solution: (45 / 50) × 100 = 90%. You got 90% on the test.
Possible Questions from Learners
- What if the total value is not 100?
- You still use the same formula. Divide your value by the total value and then multiply by 100 to get the percentage.
- How do you find what the ‘part’ is if you know the ‘whole’ and the percentage?
- Use the formula: Part = (Percentage × Total Value) / 100.
- Can a percentage be more than 100?
- Yes, if the value is more than the total value, the percentage will be greater than 100%.
Practice Problems
Now let’s practice calculating percentages with a few problems.
- You have a pizza with 8 slices and you ate 3. What percentage of the pizza did you eat?
- A store is having a 25% off sale. If a shirt originally costs $40, how much do you pay after the discount?
- A school has 600 students, 60% of whom are girls. How many girls are there in the school?
Solutions to Practice Problems
- Solution: (3 / 8) × 100 = 37.5%. You ate 37.5% of the pizza.
- Solution: Discount = (25 / 100) × $40 = $10. You pay $40 – $10 = $30 after the discount.
- Solution: Number of girls = (60 / 100) × 600 = 360. There are 360 girls in the school.
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