A store entrusts a moving station to deliver 400 porcelain bowls. The shipping fee for each bowl is 0.15 yuan, and 1.05 yuan will be deducted for each broken porcelain bowl. At the end of the checkout, the handling station gets a total shipping fee of 56.4 yuan. Porcelain bowl?
某商店委托搬运站运送400个瓷碗，每个瓷碗的运费是0.15元，每破损1个瓷碗要倒扣1.05元，最后结账，搬运站共得运费56.4元，搬运中破损了几个瓷碗？
<gadget id="calculator">400 * 0.15</gadget>
<output>60</output>

<gadget id="calculator">60 - 56.4</gadget>
<output>3.6</output>

<gadget id="calculator">0.15 + 1.05</gadget>
<output>1.2</output>

<gadget id="calculator">3.6 / 1.2</gadget>
<output>3</output>

<result>3</result>