The school library bought 250 science and technology books, and the number of story books bought was less than that of science and technology books (2/5). How many fewer story books were bought than science and technology books?
学校图书馆买来科技书250本，买来的故事书比科技书少(2/5)，买来的故事书比科技书少多少本？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">250 * (2/5)</gadget>
<output>100</output>

<result>100</result>