Divide the natural numbers 1, 2, 3, ..., 998, 999 into three groups. If the average numbers of each group are exactly equal, what is the sum of the three average numbers.
把自然数1，2，3，…，998，999分成三组，如果每一组数的平均数恰好相等地，那么这三个平均数的和是多少．
<gadget id="calculator">333 / 333</gadget>
<output>1</output>

<gadget id="calculator">500 * 1</gadget>
<output>500</output>

<gadget id="calculator">500 * 3</gadget>
<output>1_500</output>

<result>1_500</result>