The way it works is; Say you made 500 trades over the last financial year with the following results.
200 winning trades with a total gain of $60K
300 losing trades with a total loss of $90k
Net result for year - loss of $30k
You can be classified as a trader for tax purposes as you have made a $60k profit on trading but you can also claim your net loss of $30k for the year against your taxable income.