The fruit shop shipped a batch of apples, sold (2/5) of the total on the first day, and sold (1/2) of the first day on the second day. What percentage of this batch of apples is left unsold?
水果店运来一批苹果，第一天卖出总数的(2/5)，第二天卖出的是第一天的(1/2)．还剩这批苹果的几分之几没有卖？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">1 - (2/5) - (1/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>