The oxidation numbers of oxygen atoms in hydrogen peroxide, respectively, are 

The chemical name for hydrogen peroxide is ${\mathrm{H}}_2{\mathrm{O}}_2$
H has an oxidation number of 1, but when mixed with fewer electronegative elements, it becomes negative.
Since oxygen has a greater electronegative charge than hydrogen, the amount of hydrogen that is oxidised in ${\mathrm{H}}_2{\mathrm{O}}_2$ be X.
Let the amount of oxygen for oxidation in.
As a result, the total number of oxidations for all the atoms in a neutral chemical is zero.

$\begin{array}{l}\therefore (\mathrm{x}\times 2)+\left(\right(+1)\times 2)=0\\ \Rightarrow 2\mathrm{x}+2=0\\ \Rightarrow \mathrm{x}=-1\end{array}$