If two $1 coins are tossed at the same time, what is the probability that both are heads
两枚1元硬币同时抛下，两枚都是正面向上可能性为多少
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>