If two one-dollar coins are thrown on the ground at the same time, what is the probability that both coins will face up?
将两枚一元的硬币同时抛在地上，两枚硬币都是"1元"字样朝上的可能性是多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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