Wang Yong went to the stationery store and first bought a diary for 30 yuan, and then bought 3 ballpoint pens of the same type for 18 yuan. How much is each diary more expensive than each ballpoint pen?
王永到文具店先买了一本日记本，用去30元，又买了3支同样的圆珠笔，用去18元．问每本日记本比每支圆珠笔贵多少元？
<gadget id="calculator">18 / 3</gadget>
<output>6</output>

<gadget id="calculator">30 - 6</gadget>
<output>24</output>

<result>24</result>