Get your taxes done using TurboTax

For the sake of this example, I am presuming that your gambling wins = IRS form 1099-K.

To report the receipt of the 1099-K in TurboTax Online, follow these steps that record the IRS form 1099-K funds as other income.

• Down the left side of the screen, click Federal.
• Down the left side of the screen, click Wages & Income.
• Click Show more to the right of Other Common Income.
• Under Your income and expenses, click the Edit/Add button to the right of Form 1099-K.
• At the screen Did you get a 1099-K? click Yes.
• At the screen How would you like to enter your 1099-K? click Type it in myself.  Click Continue.
• At the screen Choose which type of income your 1099-K is for, select the button for Other income.  Click Continue.
• At the screen Let’s get the info from your 1099-K, enter the information.      Click Continue.
• At the screen Your Other 1099-K income, you enter further information for the Other income.  Click Continue.
• At the screen Your 1099-K summary, notice that the income relates to Other income.  Click Done.

The entry will be reported:

• on line 8z of Schedule 1 of the Federal 1040 tax return, and 
• on line 8 of the Federal 1040 tax return.

You want to report the full amount of the 1099-K because the IRS will be looking for that to be reported on your tax return.  Then reverse out the incorrect amount.  So you would report $100 in income and $-100 as the reversal.  Make sure that you retain documentation to justify your actions.

Other income may need to be reversed if some or all the income reported on the 1099-K is not accurate.  Post the negative entry as follows:

• Down the left side of the screen, click Federal.
• Down the left side of the screen, click Wages & Income.
• Click Show more to the right of Less Common Income.
• To the right of Miscellaneous Income, 1099-A, 1099-C, click the Start / Revisit button.
• To the right of Other reportable income, click the Start / Revisit button.
• At the screen Other Taxable Income, enter a description such as “Incorrect form 1099-K [amount]” and a negative amount. 

The entry will be reported:

• on line 8z of Schedule 1 of the Federal 1040 tax return, and 
• on line 8 of the Federal 1040 tax return.

So now you have reported the IRS form 1099-K and notified the IRS of the reversal.  Then you report the same $100 as gambling income as described by @LenaH above

@skisbosco