Common errors in bookkeeping include single-entry error, where only one part of a transaction is recorded. It can be detected by the amont of the transaction equalling the difference in balance between the two sides of the worksheet. A double-entry error occurs when a transaction is recorded twice on the same side of the worksheet. A transposition error (e.g., 35 recorded as 53) is detected when the differences in both sides of the worksheet is divisible by 9. Addition and subtraction errors are largely avoided with the introduction of electronic spreadsheets.