Answer: Ricardo put 8 books on each shelf.
Step-by-step explanation:
Given: Number of books = 32
Number of shelves = 4
We use division operation to divide an amount into different sections equally.
By division operation,
The number of books put on each shelf = (32) ÷ 4
i.e. The number of books put on each shelf = 8
Therefore, Ricardo puts 8 books on each shelf.