The Allowance for Bad Debts account had a balance of $6,300 at the beginning of the year and $8,100 at the end of the year. During the year (including the year-end adjustment), bad debts expense of $11,400 was recognized. Required: Calculate the total amount of past-due accounts receivable that were written off as uncollectible during the year. (Hint: Make a T-account for the Allowance for Bad Debts account, plug in the amounts that you know, and solve for the missing amount.)