Percentages

Understanding Percentages

A percentage is a way of expressing a number as a part of 100. The word "percent" comes from Latin and means "per hundred." So, when you see something like $45\%$, it simply means 45 out of 100.

Think of percentages as pieces of a whole pie, where the whole pie represents $100\%$. If you eat $25\%$ of the pie, you’ve eaten 25 out of 100 pieces!

The Percent Symbol (%)

The symbol % stands for "percent," and it represents a fraction with a denominator of 100. So, we can write: $$45\% = \frac{45}{100} = 0.45$$

 

Why Do We Use Percentages?

Percentages make it easy to compare different amounts on the same scale. For example, comparing scores on a test:

• Alice scored $80\%$
• Bob scored $90\%$

It’s clear from the percentages who scored higher, no matter how many questions were on the test