In a cuboid glass tank with a length of 50 cm and a width of 40 cm, a cube iron block with a side length of 20 cm is put into it. At this time, the water depth is 18 cm. If the iron block is taken out, how many cm is the water depth in the tank?
在一个长50厘米、宽40厘米的长方体玻璃缸中，放入一块棱长为20厘米的正方体铁块，这时水深18厘米，若把铁块取出，缸中的水深是多少厘米？
<gadget id="calculator">50 * 40 * 18</gadget>
<output>36_000</output>

<gadget id="calculator">20 * 20 * 20</gadget>
<output>8_000</output>

<gadget id="calculator">36_000 - 8_000</gadget>
<output>28_000</output>

<gadget id="calculator">50 * 40</gadget>
<output>2_000</output>

<gadget id="calculator">28_000 / 2_000</gadget>
<output>14</output>

<result>14</result>