Packing problem 1

$\begin{aligned} \left \lfloor \cfrac{10}{1} \right \rfloor \cdot \ \left \lfloor \cfrac{10}{1} \right \rfloor \cdot \left \lfloor \cfrac{10}{4} \right \rfloor & =?= 250 \\ 10 \cdot 10 \cdot 2 & =? = 250 \\ 200 & \ne 250 \end{aligned}$

Hence, the 250 bricks can't be perfectly pack into $10 \times 10 \times 10$ box .

You can fit the first 200 by making 2 layers of 10x10x4. Then there are 2 layers left. By placing the side of length 4 down you can fit another 20 per layer, so that makes 240 in total. Now there is a small space left in which you can fit another 4 per layer. This makes room 4 248 bricks in total leaving 8 unit squares which form a 2x2x2 cube.