This document discusses various types of accounting errors and how to rectify them. It outlines two main types of errors: two-sided errors, which do not affect the trial balance, and one-sided errors, which do affect the trial balance. Two-sided errors include errors of omission, commission, original entry, principle, and compensating errors. One-sided errors require using a suspense account to rectify. The document provides examples for each type of error and explains how to make the correcting journal entries to rectify the errors.