Percentage is the base chapter behind profit and loss, discount, SI-CI, ratio, and data interpretation. Once the conversion logic becomes automatic, many arithmetic questions get faster.
Core concepts
- Understand percentage as 'per hundred' and connect it with fraction and decimal.
- Learn increase and decrease logic before jumping to word problems.
- Use benchmark values like 10%, 20%, 25%, 33.33%, 50%, and 75% for mental speed.
Must-remember formulas
- x% of y = (x/100) × y
- Percentage change = (Change / Original value) × 100
- New value = Original × (100 ± percentage) / 100
Fast tricks
- 25% means one-fourth, 12.5% means one-eighth, and 75% means three-fourths.
- If the denominator becomes 100 easily, the percentage becomes visible immediately.
- For repeated increase and decrease, do not cancel blindly. Work with net multiplier.
Worked examples
- Find 25% of 320. Since 25% = 1/4, the answer is 80.
- A number increases from 200 to 250. Increase = 50, so percentage increase = 25%.
Practice section
- Find 12.5% of 560.
- A price falls from 480 to 408. Find the percentage decrease.
- What percent of 240 is 36?
Cluster articles
- Percentage Tricks for Fast Calculation
- Percentage Formulas You Must Remember
- Common Percentage Mistakes in Exams
- Percentage Shortcuts for Arithmetic Speed
- Percentage Word Problems Explained
- Exam-Based Percentage Questions
- Previous Year Percentage Question Patterns
- Percentage Practice Set 1
- Percentage Practice Set 2
- Percentage Speed Tricks for Last-Minute Revision