It costs 25 yuan to buy a ballpoint pen and a fountain pen, and 2.65 yuan to buy a ballpoint pen. How much is a fountain pen more expensive than a ballpoint pen?
买一枝圆珠笔和一枝钢笔共需要25元，买一枝圆珠笔需要2.65元，一枝钢笔比一枝圆珠笔贵多少元．
<gadget id="calculator">25 - 2.65 - 2.65</gadget>
<output>19.7</output>

<result>19.7</result>