Teacher Wang spent 25.5 yuan to buy 3 diaries and 16.65 yuan to buy 3 pens. Who is more expensive than a diary and a pen? How much is it expensive?
王老师买3本日记本用去25.5元，买3支钢笔用去16.65元．一本日记本和一支钢笔谁贵？贵多少元？
<gadget id="calculator">25.5 / 3</gadget>
<output>8.5</output>

<gadget id="calculator">16.65 / 3</gadget>
<output>5.55</output>

<gadget id="calculator">8.5 - 5.55</gadget>
<output>2.95</output>

<result>2.95</result>