When subtracting 2487 from a number, the sloppy calculation mistakenly changed the numbers in the hundreds and tens places to be subtracted, and the result was 8439. What should be the correct number?
一个数减去2487，小马虎计算时错把被减数百位和十位上的数换了，结果得到8439，正确得数应是多少．
<gadget id="calculator">10_296 - 2_487</gadget>
<output>7_809</output>

<result>7_809</result>