If a coin is tossed 3 times, 2 heads and 1 tail, what is the probability of the 4th coin toss being heads?
任意向上掷3次硬币，有2次正面向上，1次反面向上，那么第4次掷硬币时正面向上的可能性是多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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