A book has 30 pages, after reading (1/10) of this book, how many pages are left
一本书30页，看了这本书的(1/10)，还剩多少页
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">30 * (1/10)</gadget>
<output>3</output>

<gadget id="calculator">30 - 3</gadget>
<output>27</output>

<result>27</result>