Mr. Wang bought 8 fountain pens and 9 ballpoint pens and shared them for 285 yuan. Ballpoint pen share to 45 yuan. How much is each fountain pen more expensive than a ballpoint pen?
王老师买了8支钢笔和9支圆珠笔，共用去285元．圆珠笔共用去45元．每支钢笔比圆珠笔贵多少元？
<gadget id="calculator">285 - 45</gadget>
<output>240</output>

<gadget id="calculator">240 / 8</gadget>
<output>30</output>

<gadget id="calculator">45 / 9</gadget>
<output>5</output>

<gadget id="calculator">30 - 5</gadget>
<output>25</output>

<result>25</result>