When subtracting 3218 from a number, Xiaojun mistakenly swapped the tens and ones digits of the subtrahend, and the result is 4039. What is the correct result?
一个数减去3218，小军在计算时错把被减数的十位和个位上的数交换了，结果得4039，正确的结果是多少？
<gadget id="calculator">7_275 - 3_218</gadget>
<output>4_057</output>

<result>4_057</result>