For a basket of cantaloupe, 50% of the whole basket is sold for the first time, and the second time is 3/5 of the first sold quantity. What fraction of the basket of cantaloupe is left?
一筐香瓜，第一次卖出全部的50%，第2次卖出的是第一次卖出数量的(3/5)，还剩这筐香瓜的几分之几？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(1/2) * (3/5)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/2) - (3/10)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>