Problem:
Laura added two three-digit positive integers. All six digits in these numbers are different. Laura's sum is a three-digit number . What is the smallest possible value for the sum of the digits of ?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Because has to be greater than , the digit sum has to be at least , and an example like shows that is indeed the smallest possible value.
The problems on this page are the property of the MAA's American Mathematics Competitions