To dig a canal, the full length (1/3) has been completed, and there are still 70 kilometers away from the midpoint. How many kilometers have been completed?
挖一条水渠，已完成了全长的(1/3)，离中点还有70千米，已完成了多少千米？
<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">70 / (1/6)</gadget>
<output>420</output>

<gadget id="calculator">420 * (1/3)</gadget>
<output>140</output>

<result>140</result>