1.6 Extra Practice
Regular, daily practice is much better for learning and long-term memory than "massed practice", which is a fancy word for cramming.
Massed practice: A fancy name for cramming.
That's why you should login every day and solve a few problems in this textbook. Re-solving old problems is great for learning, but you might also want to keep trying new problems.
That's what this section is for. These problems are just here to give you more to practice on.