The electrical appliance shopping mall plans to sell 20,000 electrical appliances throughout the year, but actually completed 60% of the plan in the first half of the year. According to the sales situation in the first half of the year, how many more electrical appliances will be sold in the whole year than planned?
电器商场计划全年出售电器20000台，实际上半年就完成了计划的60%，按上半年销售情况估计，全年比计划多销售电器多少台？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) - 1</gadget>
<output>-2/5 = around -0.4</output>

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

<gadget id="calculator">20_000 * (1/5)</gadget>
<output>4_000</output>

<result>4_000</result>