If 0 to 3 can be used to form many four-digit numbers without repeating numbers, what is the average of all these four-digit numbers?
用0到3可以组成许多没有重复数字的四位数，则所有这些四位数的平均数是多少．
<gadget id="calculator">1_023 + 1_032 + 1_203 + 1_230 + 1_302 + 1_320 + 2_013 + 2_031 + 2_103 + 2_130 + 2_301 + 2_310 + 3_012 + 3_021 + 3_102 + 3_120 + 3_201 + 3_210</gadget>
<output>38_664</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<gadget id="calculator">38_664 / 18</gadget>
<output>2_148</output>

<result>2_148</result>