A three-digit number, after the ones and hundreds digits are exchanged, is still a three-digit number. The ones digit of the difference between it and the original three-digit number is 7. Try to find their difference.
一个三位数，个位和百位数字交换后还是一个三位数，它与原三位数的差的个位数字是7，试求它们的差．
<gadget id="calculator">99 * 3</gadget>
<output>297</output>

<result>297</result>