Xiaohu bought a copy of "Mystery of the Insect Kingdom", he paid the salesperson 10 yuan, and got back 2.55 yuan. How much is this book?
小虎买一本《昆虫王国的奥秘》，他付给营业员10元，找回2.55元．这本书多少钱？
<gadget id="calculator">10 - 2.55</gadget>
<output>7.45</output>

<result>7.45</result>