(1/7) of a book is 25 pages, how many pages are (2/5) of it.
一本书的(1/7)是25页，它的(2/5)是多少页．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">25 / (1/7)</gadget>
<output>175</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">175 * (2/5)</gadget>
<output>70</output>

<result>70</result>