A story book is 3.78 yuan, which is 5.02 yuan cheaper than a science book. How much are the two books in total?
一本故事书3.78元，比一本科技书便宜5.02元，两本书共多少元？
<gadget id="calculator">3.78 + 5.02 + 3.78</gadget>
<output>12.58</output>

<result>12.58</result>