A batch of fruit weighs 400 kilograms. 20% of the total quantity is sold on the first day, and the remaining 50% is sold on the second day. How many kilograms are left unsold.
一批水果重400千克，第一天卖了总量的20%，第二天卖了余下的50%，还剩多少千克没有卖掉．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(4/5) * (1/2)</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">400 * (2/5)</gadget>
<output>160</output>

<result>160</result>