What is a Percentage?
The word percent means “out of 100.”
The symbol for percent is:
%
Example:
50%
This means:
50 out of 100
Percentages help us compare quantities quickly and easily.
Understanding Percentages
A percentage tells us how much of a whole we have when the whole is divided into 100 equal parts.
Examples:
| Percentage | Meaning |
|---|---|
| 100% | The whole amount |
| 50% | Half |
| 25% | One quarter |
| 75% | Three quarters |
Percentages, Fractions, and Decimals
Percentages are connected to fractions and decimals.
| Percentage | Fraction | Decimal |
|---|---|---|
| 50% | 1/2 | 0.5 |
| 25% | 1/4 | 0.25 |
| 75% | 3/4 | 0.75 |
| 10% | 1/10 | 0.1 |
Understanding these connections helps students move between different forms of numbers.
Converting Percentages to Decimals
To convert a percentage into a decimal:
- divide by 100
- move the decimal point two places to the left
Examples:
50% = 0.50 = 0.5
25% = 0.25
80% = 0.80 = 0.8
Converting Percentages to Fractions
Write the percentage over 100 and simplify if possible.
Examples:
25% = 25/100 = 1/4
50% = 50/100 = 1/2
75% = 75/100 = 3/4
Finding Percentages of Numbers
To find a percentage of a number:
- Change the percentage to a decimal
- Multiply
Example:
50% of 20
= 0.5 × 20
= 10
Answer: 10
Real-Life Uses of Percentages
Percentages are used in many areas of life:
| Situation | Example |
|---|---|
| Shopping | 20% discount |
| School | Test scores |
| Sports | Winning percentages |
| Banking | Interest rates |
| Technology | Battery percentage |
| Weather | Chance of rain |
Understanding Discounts
Stores often use percentages to advertise sales.
Example:
A shirt costs $40.
There is a 25% discount.
25% of $40:
= 0.25 × 40
= 10
Discount = $10
New price:
$40 − $10 = $30