Bottom row 5 (first box) there is an empty box in allowance for doubtful accounts what do I put in that box?

Score: 15/19 Evers Industries Estimate of Allowance for Doubtful Accounts Days Past Due Days Past Due Not Past Due 1-30 31-60 Days Past Due Days Past Due 61-90 Balance Over 90 Total receivables 1,147,400.00 610,600.00 236,400.00 120,300.00 105,300.00 74,800.00 Percentage uncollectible 3.0% 4.0% 18.0% 38.0% 90.0% Allowance for $18,318.00 $9.456.00 $21,654.00 $40.014.00 $67,320.00 doubtful accounts