Find a pair of 3 digit numbers that have an estimated difference of 520

The three digit number is such that it takes the general form of,
     100x + 10y + z
where x is the hundreds digit
           y is the tens digit, and 
           z is the ones digit

If we have one of the three digit numbers as 100 (being the smallest), we determine the second number by adding 520 to 100 which gives us an answer of,
       620

Therefore, one pair of these numbers is 620 and 100.