find the sum of A+M+C

Question

The sum of 5- digit numbers AMC10 and AMC12 is 123422

Answer 1

Note that AMC12 and AMC10 only differ by 2. So divide 123422 by 2 and the quotient will be AMC11. Subtract one from the quotient and you have AMC10. Add one to the quotient and you have AMC12. Add them together to be sure they add to 123422. Now you know what A, M, and C are, so just add them.

A + M + C = ___?

There are other ways to do it, but this was the simplest.