Question 780796
The largest possible even number will end in an even number, and have the largest possible first digit.  5 is the largest digit, so make that the first digit.  Since both 4 and 2 are even, so either could be the final digit, use the 4 for the second digit, because 4 is the largest remaining digit.  The number has to end with the 2.<P>
5412<P>
900 greater than that is 5412 + 900 = 6312