Percentages
Percent of a number, increase/decrease, sales tax and tips, and percent word problems.
This page is a free outline of what the Percentages lesson covers — it is not the lesson itself. The interactive lesson, practice, quizzes, and AI Tutor are inside the app.
This lesson covers
- Converting Between Number Types Convert between fractions, decimals, and percents — e.g., 3/4 = 0.75 = 75%.
- Interest – Compound Interest that earns interest — figured on the growing balance each period, not just the original amount.
- Interest – Simple Interest paid only on the original amount. Formula: I = P × r × t (principal × rate × time).
- Percent – Finding a Percent of a Number
- Percent – Increase and Decrease
- Percent – Word Problems Percent questions in sentence form — find the part, the whole, and the percent.
- Percent – Sales Tax and Tips Add a percent of the bill: find the percent, then add it on (or multiply by 1.08 for 8%).
- Solving Proportions A proportion sets two ratios equal (2/3 = x/9). When one value is missing, cross-multiply — multiply diagonally across the equals sign — then divide to find it.
Linked concepts (purple →) have a full explanation. Hover or tap a dotted ⓘ concept for a quick definition.
Inside the app, Percentages comes with:
Read the explanation here for free — then practice it for real, with everything you need in one place.
24/7 AI Tutor — Ask anything and get a step-by-step explanation when you’re stuck — it teaches the concept, not just the answer. Every answer verified by three independent AIs.
- Practice sets — Open-book practice questions at your level, easiest-first — as many as you want, never scored.
- Quizzes — Scored quizzes on the whole lesson, so you know when you’re ready to move on.
- Skills Check — A concept-by-concept map of what you’ve mastered and what to focus on next.
- Worked examples — Tap the Brain Button on any example for alternative step-by-step explanations.
- Glossary — Plain-English definitions of every key term in the lesson.
- Formula sheet — The GED® & HiSET® formula sheets, on screen while you practice.
- Practice calculator — An on-screen calculator to build your calculator skills before test day.
- Math-fact flashcards — Quick drills for addition, multiplication, perfect squares, and square roots.
Practice Percentages with your AI Tutor
Interactive lessons, quizzes, and a 24/7 AI Tutor — every answer verified by three independent AI systems. Currently free for individual users.
Create your free account →