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Lesson 3

Finding Percentage of a Number

Calculate what X% of a number equals.

  • beginner

Formula

X% of Y = (X ÷ 100) × Y

📚 Finding X% of a Number

To find a percentage of a number, convert the percentage to a decimal and multiply.

X% of Y = (X ÷ 100) × Y

Example: What is 20% of 150?

1
Convert 20% to decimal: 20 ÷ 100 = 0.20
2
Multiply: 0.20 × 150 = 30

Quick Mental Math Trick:

To find 10% of any number, just move the decimal point one place left.

10% of 250 = 25

Then for 20%, just double it: 20% of 250 = 50

Frequently Asked Questions

How do I find a percentage of a number?

Turn the percentage into a decimal and multiply: 15% of 80 is 0.15 × 80 = 12.

What is a quick way to find 10% or 5% of a number?

For 10%, move the decimal point one place to the left, so 10% of 250 is 25. For 5%, take half of that: 12.5. Other percentages can be built from these pieces.

Practice

Work each one out, then check yourself.

  1. What is 25% of 200?

    Hint: 25% = 0.25, so multiply 0.25 × 200

    Show answer

    50

  2. What is 15% of 80?

    Hint: 10% of 80 = 8, 5% = 4, so 15% = 8 + 4

    Show answer

    12

Final Quiz

0/3

Test what you learned. Pick the correct answer for each question.

  1. What is 20% of 250?

    What is 20% of 250?

  2. What is 15% of 80?

    What is 15% of 80?

  3. Tip is 18%. The bill is $50. How much is the tip?

    Tip is 18%. The bill is $50. How much is the tip?