P + Q means P is sister of Q.

P – Q means P is son of Q.

P × Q means P is husband of Q.

P ÷ Q means P is mother of Q.

If P + Q ÷ R – S – A × B, then how is B related to Q?

Mother in law

Note:

↑ or ↓ ⇒ Upward or downward line shown "generation gap" .

   =    ⇒ Double lines shown "relation b/w Husband & Wife"

   —   ⇒ single line shown "relation between them other than Husband & Wife".

If R is son of Q and S both. So, S must be her (Q) husband and A is husband,