Xiaogang buys a ballpoint pen and a fountain pen, and the total cost is 18 yuan. It is known that the price of buying a fountain pen can buy 8 ballpoint pens. How much is a ballpoint pen?
小刚买一支圆珠笔和一支钢笔，一共用去18元．已知买一支钢笔的价钱可以买8支圆珠笔，一支圆珠笔多少钱？
<gadget id="calculator">18 / 9</gadget>
<output>2</output>

<result>2</result>