Question 75
a) Given the ten digits from $0$ to $9$, prove that three numbers $A$, $B$, and $C$ can be formed by combining these digits, provided that each digit is used exactly once and $A+B=C$. Notice that $0$ may not be the first digit of any of the numbers.
b) Find all possible values of the sum of the digits of $C$.
b) Find all possible values of the sum of the digits of $C$.