Final answer:
To calculate the total number of children's books that need replacement each year, divide the total number of books by the number of years.
Step-by-step explanation:
To calculate the total number of children's books that need replacement each year, you can divide the total number of books by the number of years. In this case, we have 1,000 physical children's books that need replacement after eight years. So, the calculation would be: 1,000 books / 8 years = 125 books per year.