This is a series of regular numbers: 1, 4, 7, 10, ... 1996, 1999, 2002, what is the average of this series of numbers?
这是一串有规律的数：1，4，7，10，…1996，1999，2002，则这列数的平均数是多少．
<gadget id="calculator">1 + 2_002</gadget>
<output>2_003</output>

<gadget id="calculator">668 / 2</gadget>
<output>334</output>

<gadget id="calculator">2_003 * 334</gadget>
<output>669_002</output>

<gadget id="calculator">669_002 / 668</gadget>
<output>2_003/2 = around 1_001.5</output>

<result>2_003/2 = around 1_001.5</result>