To pave a road, 6 kilometers have been paved, and the full length (2/5) has been paved. How many kilometers are left?
铺一条公路，已经铺了6千米，正好铺了全长的(2/5)，还剩多少千米．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">6 / (2/3)</gadget>
<output>9</output>

<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<result>3</result>