Student success and attempts on hundreds of online homework problems housed in a fully interactive online textbook, Material and Energy Balances zyBook, were studied over three cohorts of students (n=284). Auto-graded homework questions with randomized numbers and content can explore proficiency in the course material. Students are allowed to attempt any question as many times as needed, and a median success of 94% was found. Also, students completed thousands of attempts after correctly answering without the incentive to improve grades.