The correct formal charges on oxygen atoms numbered 2 , 1 and 3...

The formal charge (FC) on an atom in a Lewis structure is given by the formula:

$FC = V - L - \dfrac{S}{2}$

where $V$ is the number of valence electrons, $L$ is the number of non-bonding electrons, and $S$ is the number of shared (bonding) electrons.

For oxygen, the number of valence electrons is $V = 6$.

For oxygen atom $1$ (central atom):
It has $1$ lone pair ($2$ non-bonding electrons)$and 3$ bonds ($6$ shared electrons).
$FC_{1} = 6 - 2 - \dfrac{6}{2} = +1$

For oxygen atom $2$ (left atom):
It has $2$ lone pairs ($4$ non-bonding electrons)$and 2$ bonds ($4$ shared electrons).
$FC_{2} = 6 - 4 - \dfrac{4}{2} = 0$

For oxygen atom $3$ (right atom):
It has $3$ lone pairs ($6$ non-bonding electrons)$and 1$ bond ($2$ shared electrons).
$FC_{3} = 6 - 6 - \dfrac{2}{2} = -1$

The formal charges on oxygen atoms numbered $2$, $1$, and $3$ respectively are $0, +1, -1$.

Answer: $0, +1, -1$