$A$ is the father of $X$; $B$ is the mother of $Y$. The sister of $X$ and $Z$ is $Y$. Which of the following statements is definitely not true?

$A \div B$ means $A$ is the father of $B$,$A - B$ means $A$ is the wife of $B$,$A \times B$ means $A$ is the brother of $B$,$A + B$ means $A$ is the daughter of $B$.
If $P \times R \div Q$,which of the following statements is true?

In a family,there are six members $A, B, C, D, E$ and $F$. $A$ and $B$ are a married couple,$A$ being the male member. $D$ is the only son of $C$,who is the brother of $A$. $E$ is the sister of $D$. $B$ is the daughter-in-law of $F$,whose husband has died.
How is $F$ related to $C$?

$A$ is the son of $B$. $C$,$B$'s sister,has a son $D$ and a daughter $E$. $F$ is the maternal uncle of $D$. How is $E$ related to $F$?

$I.$ $A, B, C, D, E$ and $F$ are six members of a family.
$II.$ One couple has parents and their children in the family.
$III.$ $A$ is the son of $C$ and $E$ is the daughter of $A$.
$IV.$ $D$ is the daughter of $F$ who is the mother of $E$.
Which of the following pairs are the parents of the children?

$A$ is the brother of $R$. $C$ is the mother of $B$. $M$ is the sister of $C$. How is $M$ related to $B$?