The school spent a total of 660 yuan on sporting goods, including 18 pairs of badminton rackets. For each payment of 20 yuan, they bought 25 pairs of table tennis rackets. How much is each pair of table tennis rackets?
学校买体育用品一共用去660元，其中买18副羽毛球拍，每付20元，又买25副乒乓球拍，每副乒乓球拍多少元？
<gadget id="calculator">18 * 20</gadget>
<output>360</output>

<gadget id="calculator">660 - 360</gadget>
<output>300</output>

<gadget id="calculator">300 / 25</gadget>
<output>12</output>

<result>12</result>