Hongxing Primary School held a sports meeting, and each of the students in Class 5 and 2 participated in one. Among them, those who participated in the track competition accounted for the whole class (3/14), those who participated in the field competition accounted for the whole class (2/7), and the rest participated in the gymnastics performance. What percentage of the whole class take part in the gymnastics performance?
红星小学举行运动会，五2班同学每人都参加了一项．其中参加径赛的占全班人数的(3/14)，参加田赛的占全班人数的(2/7)，其余的参加体操表演．参加体操表演的占全班人数的几分之几？
<gadget id="calculator">3 / 14</gadget>
<output>3/14 = around 0.214286</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (3/14) - (2/7)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>