A TV factory produced 42,000 TVs in the first half of the year and 56,000 TVs in the second half of the year. A total of 82,400 units were sold throughout the year, how many units are still not sold?
某电视机厂上半年生产了42000台电视机，下半年生产了56000台电视机．全年共卖出82400台，还有多少台没有卖出？
<gadget id="calculator">56_000 - 82_400</gadget>
<output>-26_400</output>

<gadget id="calculator">42_000 + (-26_400)</gadget>
<output>15_600</output>

<result>15_600</result>