Question

If  A = [(2,3),(1,2)], B=[(1,3,2),(4,3,1)], C=[(1),(2)], D=[(4, 6, 8), (5, 7, 9)], then which of the sums A + B, B + C, C + D and B + D is defined?

Answer 1

Only B + D is defined since matrices of the same order can only be added.