Dad bought 6 books for 24 yuan, and Dongdong bought 1 book for 5 yuan. Which one of them bought the most expensive book? How much is it expensive?
爸爸花了24元买了6本书，冬冬花了5元买了1本书．他们谁买的书贵？贵多少元？
<gadget id="calculator">24 / 6</gadget>
<output>4</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<result>1</result>