* Oxygen's Oxidation Number: Oxygen typically has an oxidation number of -2 in compounds, except in peroxides.

* Hydrogen's Oxidation Number: Hydrogen typically has an oxidation number of +1 in compounds, except in metal hydrides.

* Overall Charge: NaOH is a neutral compound, meaning the sum of the oxidation numbers of all the atoms must equal zero.

Therefore:

* Oxidation number of Na + Oxidation number of O + Oxidation number of H = 0

* Oxidation number of Na + (-2) + (+1) = 0

* Oxidation number of Na = +1