There are some books on Xiao Ming's bookshelf, among which story books account for (1/5). If there are 20 story books, how many books are there on the bookshelf?
小明的书架上放着一些书，其中故事书占(1/5)，如果故事书放20本，那么书架上放着多少本书．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>