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Finding Percentages of Numbers

Calculate percentages of quantities in real-world scenarios.

25 minGrade 6

Introduction

Finding a percentage of a number is essential for calculating discounts, tips, taxes, and more.

The Formula

To find X% of a number, multiply the number by X/100 (or X × 0.01).

Example

20% of 80 = 80 × 0.20 = 16

Mental Math Shortcuts

For 10%, divide by 10. For 50%, divide by 2. Combine these for other percentages.

Example

15% of 200: 10% is 20, 5% is 10, so 15% is 30

Key Takeaways

  • 1Percentage of number = number × (percent ÷ 100)
  • 2Use shortcuts: 10% = ÷10, 50% = ÷2
  • 3Break complex percentages into simpler ones

Practice Problems

Test your understanding with these questions

1

What is 25% of 80?

2

A shirt costs $40. If it's 10% off, what's the discount?