Five chapters of plain-language notes — written the way you'd explain it to yourself — followed by 100 practice questions that start easy and build up to the hard ones. Read the notes, then try the problems right after.
Each chapter opens with short notes — the big idea, the formulas you actually need, one worked example, and a sticky-note tip — before the questions start. Tap Hide Notes on any chapter to skip straight to the problems. Every question still has a hint and a full explanation. Select Exit anytime to check your score so far.