The school has 684 story books and 247 science and technology books. Students have borrowed 344 of these two books. How many books are left?
学校有故事书684本，科技书247本，两种书学生共借走了344本，还剩下多少本？
<gadget id="calculator">247 - 344</gadget>
<output>-97</output>

<gadget id="calculator">684 + (-97)</gadget>
<output>587</output>

<result>587</result>