The price of a story book is 18.31 yuan, which is 1.49 yuan more expensive than a science book. How much is this science book? (First list the equations involving the unknown x, and then solve them.)
一本故事书的价格是18.31元，比一本科技书贵1.49元，这本科技书多少元？(先列出含有未知数x的等式，再解答．)
<gadget id="calculator">18.31 - 1.49</gadget>
<output>16.82</output>

<result>16.82</result>