A vegetable plot (2/7) grows celery, (3/7) grows cabbage, what percentage of the plot does not grow vegetables?
一块菜地(2/7)种芹菜，(3/7)种白菜，没种菜的占这块地的几分之几？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (2/7) - (3/7)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>