A book has 120 pages, and I have already read (2/3), and the rest should be read from the first page.
一本书120页，已经看了(2/3)，剩下的要从第多少页看起．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">120 * (2/3)</gadget>
<output>80</output>

<gadget id="calculator">80 + 1</gadget>
<output>81</output>

<result>81</result>