There are 600 story books in the library, and the number of science books is 25% of the story books. How many science books are there?
图书室有600本故事书，科技书的本数是故事书的25%，科技书有多少本？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">600 * (1/4)</gadget>
<output>150</output>

<result>150</result>