What you are describing would be true if you were a professional gambler reporting income and expenses on a Schedule C. You would have $10,100 of income and $10,000 of expenses for a net income of $100.
However, if not a professional gambler you report the $10,100 of winnings as ordinary income on the Form 1040 and the $10,000 of losses as an itemized deduction on Schedule A.
