For sports betting, your gambling income is the total of all the wins. Let's say you put $100 in an account and play $10 games. You win 20 bets and lose 20 bets. Also assume there is no juice, so your balance is $100 after those bets. You have $200 in gambling income. If you don't itemize then you can't deduct anything. This is where the TCJA raising of the standard deduction, SALT 10K limit, etc, did not help you. Even though you broke even, this is what the tax law is. Casino games may be treated different, but I don't know.
