For each situation, identify whether it is treated as a prior period adjustment or change in accounting estimate.

Upon reviewing customer contracts, the company realizes it mistakenly reported $$110,000$ of revenue instead of the actual amount earned of $$11,000.$ This mistake occurred two years ago and had a material effect on financial statements.

The company's auditors discovered that two years ago an expense was mistakenly recorded twice. This had a material effect on the income statement.

After using an expected useful life of seven years and no salvage value to depreciate its office equipment over the preceding three years, the company decided early this year that the equipment will last only two more years.