To build a 1200km canal, the full length (1/3) will be built in January, and the full length (1/4) will be built in February. How many kilometers are left?
修一条1200km的水渠，一月份修完全长的(1/3)，二月份修完全长的(1/4)，还剩多少km？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">1 - (1/3) - (1/4)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">1_200 * (5/12)</gadget>
<output>500</output>

<result>500</result>