A shopping mall held promotional activities during the May Day period, randomly selected a day from the 1st to the 7th, and all customers who shopped on this day were free. If you participate in this activity, what is the probability of winning the prize?
某商场在五一期间举办促销活动，在1日到7日随机抽出一天，在这一天购物的客户全部免费．如果你参加了这项活动，中奖的可能性是多少．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

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