The unit price of a certain fruit fell all the way after it was launched. The second week decreased by 10% compared to the first week, and the third week decreased by 10% compared to the second week. Then the unit price of this fruit decreased by a total of 100% in the second and third weeks. Several?
某种水果上市以后单价一路下跌，第二周比第一周下降了10%，第三周比第二周下降了10%，那么第二、三两周这种水果单价一共下降了百分之几？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 * (9/10) * (9/10)</gadget>
<output>81/100 = around 0.81</output>

<gadget id="calculator">1 - (81/100)</gadget>
<output>19/100 = around 0.19</output>

<result>19/100 = around 0.19</result>