A story book is 15.2 yuan, which is 1.7 yuan more expensive than a science book. How much is a science book?
一本故事书15.2元，比一本科技书贵1.7元，一本科技书多少元？
<gadget id="calculator">15.2 - 1.7</gadget>
<output>13.5</output>

<result>13.5</result>