Think of indivisible bricks, and houses:
You can cut the first house into two equal parts. But you're not strong enough to cut the second house into two equal part, since you'd be left with one brick.
For divisibility, build houses with bases containing \(m\) bricks. Then the total number of full floors is the quotient of the total number of bricks, divided by \(m\). And the remainder is the number of bricks in the floor where they aren't complete. Example with \(9\) divided by \(4\):
A number \(m\) divides a number \(t\) if and only if you can build a house with \(t\) bricks with a base made of \(m\) bricks and without having any incomplete floor.