Answer: 1. Solution. If $M=1$, then the sum $C+y+A=9$, which is only possible with the set of numbers 2, 3, 4 (in any order). If $M=2$, then the sum $C+y+A=7$, which is impossible, as this sum is not less than $1+3+4=8$. If $M>2$, this is even more impossible.
1. The sum of positive integers is 11. In the first part of this equation, identical numbers are hidden behind cards with the same letters, and different numbers - behind cards with different letters.

Consider the equation: $\quad \mathbf{C}+\mathbf{y}+\mathbf{M}+\mathbf{M}+\mathbf{A}=11$.

Can you tell which number is hidden behind the letter M?