Li Dong tossed a coin three times, one time it was tails, and the second time it was heads, what is the probability that he flipped the fourth coin and it was tails
李东抛三次硬币，1次反面朝上，2次正面朝上，那么，他抛第4次硬币反面朝上的可能性是多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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