Xiaoyue and Xiaoqing bought the same pen, Xiaoyue bought 2, Xiaoqing bought 5, Xiaoqing spent 90 yuan more than Xiaoyue, how much is this pen?
小月和小青买了同样的钢笔，小月买了2支，小青买了5支，小青比小月多花了90元，这种钢笔多少钱一支？
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">90 / 3</gadget>
<output>30</output>

<result>30</result>