Percentages
Percent problems show up everywhere: shopping, finance, data, and science. This path starts with the basics of reading percentages as parts per hundred, then moves into converting between fractions, decimals, and percents. Finish by testing your skills with visual tools and a hands-on lab that connects percent reasoning to ratios and proportions.
Learning Path
What Is a Percent?
Build intuition for how percents represent parts per hundred and how they connect to fractions and decimals.
Open →Percent Calculator & Visualizer
Plug in numbers, see the percent relationship, and check answers with a visual model.
Open →Ratio, Proportion & Percent Lab
Practice setting up proportion problems and using percent reasoning to solve them in context.
Open →Percent Essentials
Keep these core ideas handy while you work.
- Percent means "per 100": percent = part ÷ whole × 100.
- Convert by moving between forms: 25% = 0.25 = 1/4.
- For percent increase/decrease, always use the original value as the base.
More Resources
Tools
Labs
Worksheets
Cheat Sheets
Infographics
Explainers
Common Questions
How do I convert a percent to a decimal or fraction?
Move the decimal two places left to get a decimal, then write the percent over 100 for a fraction and simplify. For example, 40% = 0.40 = 40/100 = 2/5.
What's the difference between percent increase and percent decrease?
Percent increase measures how much a quantity grew compared with the original amount, while percent decrease measures how much it shrank. In both cases, the original value is the base.