I'm having issues calculating the highlight number is wrong... I calculated it via 40800-36500*0.20 that is apparently wrong as the anwser is 860. PLZ help

The following events occur for Morris Engineering during 2018 and 2019, its first two years of operations. February 2, 2018 Provide services to customers on account for $27,800. July 23, 2018 Receive $18,500 from customers on account. December 31, 2018 Estimate that 20% of uncollected accounts will not be received April 12, 2019 Provide services to customers on account for $40,800. June 28, 2019 Receive $6,000 from customers for services provided in 2018. September 13, 2019 Write off the remaining amounts owed from services provided in 2018 October 5, 2019 Receive $36,500 from customers for services provided in 2019 December 31, 2019 Estimate that 20% of uncollected accounts will not be received. value: 13.0.52 points Required information Required 1. Record transactions for each date. (If no entry is required for a transaction/event, select "No journal entry required" in the first account field.) View transaction list Journal entry worksheet 2 3 4 6 8 Estimate that 20% of uncollected accounts will not be received Note: Enter debits before credits Date General Journal Debit Credit Dec. 31, 2019 ad debt expense 860 Allowance for uncollectible accounts 860 Record entry Clear entry View general journal