It is known that the difference between two four-digit numbers is equal to 2012. So, what is the largest sum of these two four-digit numbers?
已知两个四位数的差等于2012．那么，这两个四位数的和最大是多少．
<gadget id="calculator">9_999 - 2_012</gadget>
<output>7_987</output>

<gadget id="calculator">9_999 + 7_987</gadget>
<output>17_986</output>

<result>17_986</result>