To build a 1500-meter-long road, (1/3) has already been repaired, how many meters should be repaired to make it half of the total length?
修一条1500米长的路，已经修了(1/3)，再修多少米刚好修全长的一半？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">1_500 * (1/6)</gadget>
<output>250</output>

<result>250</result>