How can I enter a loss. I try to use parenthesis, but it doesnt work???

A loss where?

 

In general, to show a loss you enter it as an expense.  If you are entering business income and expenses, then you would enter the income in the income section and the expenses in the expense section, then TurboTax will deduct the expenses and calculate any profit or loss you have.

 

If you are in the investment section you would enter the expenses in the cost basis on the same page generally that you enter your income.