There are 2,400 science and technology books in the school library, which is less than story books (1/4). How many story books are there? (solution by equation)
学校图书馆有科技书2400本，比故事书少(1/4)，故事书有多少本？(用方程解)
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">2_400 / (3/4)</gadget>
<output>3_200</output>

<result>3_200</result>