The load capacity of a truck is 4 tons, and the actual load of coal is 6 tons. Which of the following is the correct number of overloaded tons?
一辆货车的载质量是4吨，实际载煤6吨，下列叙述正确的是超载多少吨
<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<result>2</result>