A shipping company consigned 250 boxes of glass for a customer. According to the contract, the shipping fee for each box was 40 yuan. If one box was damaged, the shipping fee would not be paid and 300 yuan would be paid.
某货运公司为客户托运250箱玻璃，按合同规定每箱运费40元，若损坏一箱不但不给运费还要赔偿300元，货运公司结算时共得运费6600元，共损坏了多少箱玻璃？
<gadget id="calculator">40 * 250</gadget>
<output>10_000</output>

<gadget id="calculator">10_000 - 6_600</gadget>
<output>3_400</output>

<gadget id="calculator">300 + 40</gadget>
<output>340</output>

<gadget id="calculator">3_400 / 340</gadget>
<output>10</output>

<result>10</result>