If Kamal says,"Ravi's mother is the only daughter of my mother," how is Kamal related to Ravi?

If $A + B$ means $A$ is the sister of $B$,$A - B$ means $A$ is the brother of $B$,and $A \times B$ means $A$ is the daughter of $B$,which of the following shows the relation that $E$ is the maternal uncle of $D$?

Introducing a man,a woman said,"He is the only son of my mother's mother." How is the woman related to the man?

$A$ and $B$ are a married couple. $X$ and $Y$ are brothers. $X$ is the brother of $A$. How is $Y$ related to $B$?

$A + B$ means $A$ is the son of $B$; $A - B$ means $A$ is the wife of $B$; $A \times B$ means $A$ is the brother of $B$; $A \div B$ means $A$ is the mother of $B$; and $A = B$ means $A$ is the sister of $B$.
What does $P = R \div Q$ mean?

$A + B$ means $A$ is the son of $B$; $A - B$ means $A$ is the wife of $B$; $A \times B$ means $A$ is the brother of $B$; $A \div B$ means $A$ is the mother of $B$; and $A = B$ means $A$ is the sister of $B$.
What does $P = R + Q$ mean?