Mock AIME 1 2006-2007 Problems/Problem 2
2. Let be the sum of the digits of a positive integer . is the set of positive integers such that for all elements in , we have that and . If is the number of elements in , compute .
2. Let be the sum of the digits of a positive integer . is the set of positive integers such that for all elements in , we have that and . If is the number of elements in , compute .
Something appears to not have loaded correctly.