There are a number of trees to be planted in the park. They were planted in the morning (3/7), and the same number were planted in the afternoon as in the morning. What percentage of them are left unplanted?
公园里要种一批树，上午种了(3/7)，下午种的和上午同样多，还剩下几分之几没有种？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7) - (3/7)</gadget>
<output>1/7 = around 0.142857</output>

<result>1/7 = around 0.142857</result>