Given that a set A.B is defined as a * b = {x | x = m.n, m ∈ a.n ∈ B} if a = {4,5,6}, B = {1,2,3}, then all the elements of a are combined into?

Given that a set A.B is defined as a * b = {x | x = m.n, m ∈ a.n ∈ B} if a = {4,5,6}, B = {1,2,3}, then all the elements of a are combined into?

Is "a so elements combined" to mean "the sum of all elements"?