In each chapter there is one or more topics that are identified as a Checkpoint skill. It is a skill that students should have mastered or be close to mastering when they reach that problem in the book. It is marked in the book with a graphic check mark. The answers to the Checkpoint problems are in the Checkpoint Materials at the back of the book where you will also find more examples and more practice problems. You can look at the unit your child is in now to find the Checkpoint Problem(s) for that unit.