A kind of algae reproduces at a rate of 3 times every day, and covers the entire lake surface on the 10th day. Then, on the 8th day, the algae covers ((())/(())) of the lake surface.
一种藻类，每天以3倍的速度繁殖，第10天就覆盖完整个湖面，那么，第8天时，藻类覆盖了这个湖面的((())/(()))．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 * (1/3) * (1/3)</gadget>
<output>1/9 = around 0.111111</output>

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