A book has 60 pages. I read (1/3) of the whole book on the first day and the rest (1/4) on the second day. How many pages are left?
一本书60页，第一天看了全书的(1/3)，第二天看了余下的(1/4)，还剩下多少页？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/3) * (1/4)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/3) - (1/6)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">60 * (1/2)</gadget>
<output>30</output>

<result>30</result>