Determine the amount to be added to Allowance for Doubtful Accounts in each of the following cases and indicate the ending balance in each case.

a. Credit balance of $400 in Allowance for Doubtful Accounts just prior to adjustment. Using the aging method, the balance of Allowance for Doubtful Accounts is estimated as $7,740.

Amount added	$fill in the blank 1
Ending balance	$fill in the blank 2

b. Credit balance of $400 in Allowance for Doubtful Accounts just prior to adjustment. Bad debt expense is estimated at 2% of credit sales, which totaled $1,013,000 for the year.

Amount added	$fill in the blank 3
Ending balance	$fill in the blank 4