Xiao Ming and Xiao Liang each spend the same amount of money to buy several pens of the same price. It is known that Xiao Ming bought 30 less pens than Xiao Liang, and the money returned by Xiao Liang is 180 yuan. How much is this pen?
小明和小亮各拿出同样多的钱一起去买若干支同样价钱的钢笔，已知小明比小亮少买30支钢笔，得到小亮还给的钱是180元．这种笔每支多少元．
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">180 / 15</gadget>
<output>12</output>

<result>12</result>