Problem

Source: Singapore Junior Math Olympiad 2018 2nd Round p3 SMO

Tags: GCD, combinatorics, Product, number theory



One hundred balls labelled $1$ to $100$ are to be put into two identical boxes so that each box contains at least one ball and the greatest common divisor of the product of the labels of all the balls in one box and the product of the labels of all the balls in the other box is $1$. Determine the number of ways that this can be done.