IF we are to interpret MA as M*A as would be via standard math nomenclature, then this question is as stupid as saying
a(0) + 0 = 0 what is a? or a/0 = b what is a?
Joachim's post about asking why we were interpreting it as multiplication seems to imply that the original question that was copied was
1) Not math problem but a riddle
2) As a math problem where MA is interpreted as M * A, the initial problem violates the commutative property of multiplication, unless one of the variables is 0 (thus giving the other infinite possibilities). ie [MA + A = AM] = [(M + 1)A = MA] thus A = 0. M(0) + 0 = 0(M)