Eze and Sons extracted a trial balance as at 31 December 2023. The following errors were later discovered: (i) Salaries of ₦15,000 had been debited to the wages account (ii) A credit sale of ₦9,000 to Okoro had been completely omitted from the books (iii) The returns inwards day book had been overcast by ₦3,000 How many of these errors would cause the trial balance to disagree?

Error (i) is an error of commission — both debit entries are in expense accounts so the trial balance is unaffected. Error (ii) is an error of omission — both debit (Okoro) and credit (Sales) are omitted equally, so the trial balance still agrees. Error (iii) is an overcast of the returns inwards day book, which overstates the debit to Returns Inwards account without a corresponding overstatement on the credit side, causing the trial balance to disagree. Therefore, only one error (iii) causes disagreement.