ACT Math Percentages: Every Question Type + Free Practice Quizzes
Percentage problems appear on every ACT Math section — usually 4 to 6 questions. They range from straightforward (find 30% of 80) to deceptively tricky (a price increases 20% then decreases 20% — is it back to the original?). This guide breaks down every percentage pattern the ACT uses and links to free quizzes at each level.
The 5 ACT Percentage Question Patterns
The ACT recycles the same patterns repeatedly. Learn to recognize each one and you'll know your method before finishing the question.
| Pattern | What It Looks Like | Method |
|---|---|---|
| Find a percent of a number | "What is 35% of 240?" | Multiply: 0.35 × 240 |
| Find what percent one number is of another | "18 is what percent of 72?" | Divide: 18/72 × 100 |
| Percent change | "By what percent did sales increase?" | (new − old) / old × 100 |
| Percent markup / discount | "After a 15% discount, the price is…" | Multiply by (1 − 0.15) |
| Percent of a percent | "A increases 20%, then decreases 20%…" | Chain: × 1.20 × 0.80 (not the original) |
The Classic Trap: Percent Increase Then Decrease
This is the most common ACT percentage trick. A price increases 25% and then decreases 25% — most students say it's back to the original. It isn't.
Percent Change Formula
Memorize this and use it every time:
The formula works for both increases (positive result) and decreases (negative result). Common error: dividing by the new value instead of the old one. The denominator is always the original amount.
Related ACT Math Topics
Strengthen the skills that connect to percentages:
- Rates & Ratios — Closely related — ratios and proportions use similar fraction methods
- Averages — Weighted averages often involve percentage weights
- Word Problems — Most percentage word problems blend multiple skills