1. Assign Oxidation States to Oxygen and Hydrogen:

* Oxygen: Oxygen typically has an oxidation state of -2 in compounds, except in peroxides.

* Hydrogen: Hydrogen typically has an oxidation state of +1 in compounds, except when bonded to metals.

2. Set up an Equation:

Let 'x' represent the oxidation state of bromine. We know the overall charge of HBrO3 is 0 (it's a neutral molecule). Therefore:

(+1) + (x) + 3(-2) = 0

3. Solve for 'x':

1 + x - 6 = 0

x - 5 = 0

x = +5

Therefore, the oxidation state of bromine in HBrO3 is +5.