There used to be some story books in the class book corner, 39 of which were lent to the students, and another 50 were purchased. Now there are 95 books in the book corner. How many story books were there in the book corner?
班级图书角原来有一些故事书，借给同学们39本，又购进50本，现在图书角的书架上共有95本．图书角原来有故事书多少本？
<gadget id="calculator">95 - 50</gadget>
<output>45</output>

<gadget id="calculator">45 + 39</gadget>
<output>84</output>

<result>84</result>