A porter moved 300 pieces of porcelain and stipulated that the shipping fee for each piece was 1.5 yuan. If a piece of porcelain was damaged, not only would the shipping fee not be paid, but the compensation would be 2.5 yuan. As a result, the worker only got 378 yuan. How many pieces of porcelain did the worker damage?
一位搬运工人搬运300件瓷器，规定每件运费1.5元，若损坏一件瓷器，不仅不给运费，还要赔偿2.5元．结果这位工人只得到378元，这位工人损坏了多少件瓷器．
<gadget id="calculator">300 * 1.5</gadget>
<output>450</output>

<gadget id="calculator">450 - 378</gadget>
<output>72</output>

<gadget id="calculator">1.5 + 2.5</gadget>
<output>4</output>

<gadget id="calculator">72 / 4</gadget>
<output>18</output>

<result>18</result>