Consider the following:
P + Q means P is the Mother of Q.
P - Q means P is the sister of Q.
P * Q means P is the husband of Q.
P x Q means P is the son of Q.
What does the expression C * B + A * D mean?
AD is the mother of A
BD is the Daughter-in-law of B
CD is the Daughter of B
DD is the mother-in-law of A