1995 AHSME Problems/Problem 13
Problem
The addition below is incorrect. The display can be made correct by changing one digit , wherever it occurs, to another digit . Find the sum of and .
Solution
If we change 0 only, it would be incorrect. The same for 1, but 2 we could change to 6. If we try all the other digits, we see that it would be impossible to correct the addition. Thus and .