Percent – Finding a Percent of a Number
To find a percent of a number, convert the percent to a decimal and multiply.
This is a free explanation of Percent – Finding a Percent of a Number — a preview, not the full interactive lesson. The lesson, practice, quizzes, and AI Tutor are inside the app.
Percent literally means “per hundred”: 45% is just 45 out of every 100, or 0.45 as a decimal. To find a percent of a number, first convert the percent to a decimal, then multiply it by the number.
Dividing a percent by 100 moves the decimal point two places to the left: 30% → 0.30. Then multiplying by the quantity gives the amount you’re after.
A common mistake is forgetting to convert the percent to a decimal before multiplying — 30% of 150 requires 0.30 × 150, not 30 × 150. Skipping the conversion inflates the answer by 100 times.
Worked example
Find 30% of 150.
- Convert the percent to a decimal: 30% ÷ 100 = 0.30.
- Multiply: 0.30 × 150 = 45.
- Check: 10% of 150 = 15, so 30% is 3 × 15 = 45.
45
On the test: The GED & HiSET use percentages across data problems, finance questions, and word problems.
This concept also comes up in Data Analysis.
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- Math-fact flashcards — Quick drills for addition, multiplication, perfect squares, and square roots.
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