Arrange the 2002 numbers 1, 2, 3, ..., 2000, 2001, 2002 in a row from small to large. Calculate the average of the first 999 numbers and the average of the last 1003 numbers. What is the difference between the two averages?
将1，2，3，…，2000，2001，2002这2002个数从小到大排成一列．算出前999个数的平均数及后面1003个数的平均数，这两个平均数的差是多少．
<gadget id="calculator">1_000 + 2_002</gadget>
<output>3_002</output>

<gadget id="calculator">3_002 / 2</gadget>
<output>1_501</output>

<gadget id="calculator">999 + 1</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 / 2</gadget>
<output>500</output>

<gadget id="calculator">1_501 - 500</gadget>
<output>1_001</output>

<result>1_001</result>