For a three-digit number, the number in the ones place is four times the number in the tens place, and the number in the hundreds place is the difference between the number in the ones place and the number in the tens place. What is the largest three-digit number?
一个三位数，个位上的数字是十位上的数字的4倍，百位上的数字是个位上的数字与十位上的数字之差，这个三位数最大多少
<result>628</result>