How many pieces of such small cubes are needed to assemble a small cube with an edge length of 1 decimeter to form a cuboid with a length of 5 decimeters, a width of 4 decimeters, and a height of 2 decimeters.
用棱长是1分米的小正方体拼成长5分米，宽4分米，高2分米的长方体，一共需要用这样的小正方体多少块．
<gadget id="calculator">5 * 4 * 2</gadget>
<output>40</output>

<gadget id="calculator">1 * 1 * 1</gadget>
<output>1</output>

<gadget id="calculator">40 / 1</gadget>
<output>40</output>

<result>40</result>