Percent Increase and Decrease Quizzes

Start with the core formula: (New Value - Original Value) / Original Value × 100. Use relatable examples like a price markup on a video game or a discount on a pair of shoes. Emphasize that the 'original' value is always the denominator, as this is a common point of confusion. Visual aids like bar models can help students see the 'whole' (the original amount) and the 'part' (the change).

Effective practice includes a mix of problem types. Start with simple calculations where the original and new values are given. Then, introduce word problems involving real-world contexts like sales tax, tips, discounts, and population growth. Finally, challenge students with problems where they must find the original amount given the new amount and the percentage change.

The most frequent error is dividing the change by the new amount instead of the original amount. Students also often miscalculate the 'change' itself, for instance, by using the new value as the change. In multi-step problems, they may apply successive percentages to the original amount instead of the intermediate new amount.

This quiz can be used in multiple ways to fit your classroom needs. You can assign it as an interactive digital quiz on the Wayground platform or download it as a printable PDF for offline practice. Every quiz includes a complete answer key for quick grading and student self-assessment.

Aligned with Common Core State Standards, this topic is a key application of proportional reasoning, typically introduced in 6th or 7th grade. It builds on students' understanding of ratios and percentages and serves as a foundation for more advanced concepts in algebra, such as simple interest, exponential growth, and decay functions.

For students who need support, use Wayground's 'Reduced answer choices' feature on digital assignments to lower cognitive load. You can also create a scaffolded version of the printable quiz with a larger font or wider spacing. For advanced learners, assign problems that require finding the original price after two consecutive percentage changes, like a discount followed by sales tax.