Final Answer:
The smallest number of square boxes Antonio could have is 24, and the smallest number of rectangular boxes is 12.
Step-by-step explanation:
To find the smallest number of each type of box, we need to determine the least common multiple (LCM) of 8 and 12. The LCM is the smallest number that both 8 and 12 divide into evenly.
The prime factorization of 8 is \(2^3\) and the prime factorization of 12 is
The LCM is found by taking the highest power of each prime factor:

Therefore, the smallest number of square boxes (stacked in 8s) is 24, and the smallest number of rectangular boxes (stacked in 12s) is 12.
This ensures that Antonio can create stacks with an equal number of square and rectangular boxes, with the number of boxes in each stack being a multiple of both 8 and 12.