Solution
= Solution
The <floor function> is constant at $j$ on the four consecutive <integers> $4j,4j+1,4j+2,4j+3$. Consequently the <partition of a set> is \b[$\{\{4j,4j+1,4j+2,4j+3\}:j\in\mathbb N\}$]. Different blocks are disjoint and every <nonnegative integer> has exactly one quotient and remainder upon division by $4$.