Given that the difference between two four-digit numbers is 8912, what is the maximum value of the sum of these two four-digit numbers?
已知两个四位数的差是8912，那么这两个四位数的和的最大值是多少．
<gadget id="calculator">9_999 - 8_912</gadget>
<output>1_087</output>

<gadget id="calculator">9_999 + 1_087</gadget>
<output>11_086</output>

<result>11_086</result>