The purpose of a trial balance is to check the mathematical accuracy of the ledger by proving that total debits equal total credits after all transactions have been posted. If the debit column does not match the credit column, it indicates an error in the nominal ledger accounts. These errors may arise from incorrect postings, omissions, or calculation mistakes. They must be identified and corrected before preparing the income statement and balance sheet to ensure reliable financial information. A balanced trial balance improves confidence, supports accurate reporting, and helps prevent costly financial misstatements and compliance problems during regular accounting procedures.