An iron block with a volume of 100 cubic centimeters is immersed in a cuboid container with a length of 5 cm, a width of 4 cm, and a height of 20 cm. At this time, the height of the water surface is 12 cm. If the iron block is taken out, the height of the water surface is how many centimeters?
一个体积为100立方厘米的铁块，浸没在长是5厘米，宽是4厘米，高是20厘米的长方体容器中，这时水面高度为12厘米，如果把铁块捞出后，水面高度是多少厘米？
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">100 / 20</gadget>
<output>5</output>

<gadget id="calculator">12 - 5</gadget>
<output>7</output>

<result>7</result>