What are the oxidation numbers of nitrogen in $NH_4NO_3$?

Oxidation state of sulphur in tetrathionic acid is

The oxidation number of $S$ in Caro's acid is ..........

The oxidation number of $As$ in $H_2AsO_4^-$ is:

$A$ compound contains atoms of three elements $A$,$B$ and $C$. If the oxidation number of $A$ is $+2$,$B$ is $+5$ and that of $C$ is $-2$,the possible formula of the compound is:

Ozonolysis of $ClO_2$ produces an oxide of chlorine. The average oxidation state of chlorine in this oxide is . . . . .