What is percentage in simple words?
Before converting fractions into percentages, let's figure out what this percentage is. In fact, a percentage is also a fraction! The word itself comes from the Latin “pro centum”, which literally translates as “per hundred” or “hundredth part”.
Imagine a huge cake that was cut into exactly 100 identical small pieces. One such piece is exactly 1% (one percent) of the whole cake. Or, in the language of mathematics, this is one hundredth part (1/100).
How to convert a decimal to a percentage (Comma Rule)
With decimal fractions (these are those that are written separated by a period or comma, for example 0.5 or 0.75) everything is very simple. The magic of multiplying by 100 works here. When we multiply a decimal fraction by 100, the decimal point simply “jumps” two steps to the right.
- ➡️ Example 1: We have a fraction 0.45. Multiply by 100 (move the decimal point two places to the right) and get 45%.
- ➡️ Example 2: Fraction 0.8. Move the comma two places. But there is only one sign (eight)! Then we just add a zero at the end. It turns out to be 80%.
- ➡️ Example 3: Fraction 0.03. We move the comma, the leading zeros disappear, all that remains is 3%.
How to convert fractions to percentages
An ordinary fraction (for example, 3/4 or 1/2) consists of a numerator (the number on top) and a denominator (the number on the bottom). There are two convenient ways to convert it into percentages. Choose the one you like best!
Method 1: Convert the bottom (denominator) to a hundred
We remember that a percentage is a hundredth part. This means that we need to make sure that the number 100 appears at the bottom of the fraction. To do this, we multiply both the top and the bottom by the same number.
Example: How to translate 3/4?
We need a hundred instead of a four at the bottom. To do this, 4 needs to be multiplied by 25. Multiply the top and bottom by 25:
(3 × 25) / (4 × 25) = 75/100. And 75 hundredths is75%!
Method 2: Divide the top into the bottom (Easiest)
Any line in a fraction means division. Simply divide the top number by the bottom number (on a column or on a calculator), and then apply the “comma rule” we learned above.
Example: How to translate 2/5?
Divide 2 by 5. It turns out 0.4. Now multiply by 100 (move the decimal point) and get 40%.
Cheat table: the most common fractions
These fractions are encountered all the time at school and in life. It’s easier to memorize them once than to count them every time!
| Ordinary fraction | Decimal | Percentage (%) | What do you call this in real life? |
|---|---|---|---|
| 1/2 | 0.5 | 50% | Half |
| 1/4 | 0.25 | 25% | Quarter |
| 3/4 | 0.75 | 75% | Three Quarters |
| 1/5 | 0.20 | 20% | Fifth |
🔥 Tricky question: Can there be more 100 percent?
Of course it can! 100% is one whole. If your number is greater than one, then the percentage will be greater than one hundred. For example, the number 1.5 is 150%. And the number 2 is 200%. This often happens when prices in a store double (an increase of 200%).
Why do we need to convert fractions to percentages?
You may think that this is only needed for math tests. But in fact, you see these translations every day! Computers and smart online calculators on websites constantly do these calculations for you:
- 🔋 Phone battery: When the phone is half charged (a fraction of 1/2), the screen shows 50%.
- 🛍️ Discounts in stores: If sneakers are a quarter cheaper (a fraction of 1/4), a bright red “25% Discount” icon will hang on the display window.
- ⏳ Downloading files: When the game or movie has downloaded three quarters (3/4), the loading bar will show 75%.