Answer 1

>>> A = [[1,2],[3,4]]
>>> B = [[5,6],[7,8]]
>>> C = []
>>> for i in range(len(A)):
C.append([])
for j in range(len(A[i])):
C[i].append(A[i][j]+B[i][j])

>>> C
[[6, 8], [10, 12]]