If a coin is tossed 3 times, 2 heads and 1 tails, what is the probability of tails on the 4th toss?
投掷3次硬币，有2次正面朝上，1次反面朝上，那么投掷第4次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>