A + B means, A is sister of B.

A – B means, A is son of B.

A × B means, A is the husband of B.

A ÷ B means, A is mother of B.

P + Q ÷ R – S – T × U, then how is U related to Q ?

Mother-in-law

Explanation:

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".