There are some books on Xiao Ming's bookshelf, the number of books is 150, and (1/5) of them are story books, how many story books are there on the bookshelf?
小明的书架上放着一些书，书的本数是150本，其中(1/5)是故事书，书架上放着多少本故事书．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">150 * (1/5)</gadget>
<output>30</output>

<result>30</result>