Use a piece of iron plate with a length of 30cm and a width of 20cm, cut and splice it into a metal box with a height of 5cm without a lid.
用一块长30cm，宽20cm的铁板，剪裁拼接成一个高5cm的无盖铁盒，长宽都是整厘米数，可任意裁，铁盒容积最大是多少？
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<gadget id="calculator">20 - 10</gadget>
<output>10</output>

<gadget id="calculator">5 / 1_000</gadget>
<output>1/200 = around 0.005</output>

<gadget id="calculator">20 * 10 * (1/200)</gadget>
<output>1</output>

<result>1</result>