Redox question

Hi guys, i'm a bit stuck... i don't understand how to calculate 3 electrons. At the moment, I understand that 4 Hydrogens on the left has an oxidation state of +1.
NO^3- has an oxidation state of -1, and NO has an oxidation state of +2 and H₂O has an oxidation state of 0. But where did 3 electrons come from..? I calculated.. 2 electrons on the left hand side.

NO³⁻+ 4H⁺+ 3e⁻ → NO + 2H₂O

You are a little confused with how you are using oxidation states. Compounds and ions do not have an oxidation state. It is the elements themselves that are assigned oxidation states.

NO₃^- is an ion in which the oxidation state/number of the nitrogen atom is +5. Each of the oxygen atoms has an oxidation number of -2.

If you look at the equation above you can see that nitrogen atoms on the LHS change from oxidation state +5 to oxidation state of +2 on the RHS.

No other element changes oxidation state.

The nitrogen atom must accept 3e to go from +5 to +2.

The final equation must be balanced in terms of atoms AND charge (as the poster above stated). You can use this as a "checksum" to test your answer.