The following errors were made in preparing a trial balance: the $1,350 balance of Inventory was omitted; the $450 balance of Prepaid Insurance was listed as a credit; and the $300 balance of Salaries Expense was listed as Utilities Expense. The debit and credit totals of the trial balance would differ by ?

The answer according to our prof is supposed to be $2,250. Please show the solution for for this answer.