There are 8 white balls and 1 black ball (the same shape and size) in a small box, if you touch any ball, what is the probability of touching a black ball
小盒中有8个白球和1个黑球(形状、大小相同)，任意摸一个球，摸到黑球的可能性是多少
<gadget id="calculator">1 + 8</gadget>
<output>9</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<result>1/9 = around 0.111111</result>