"Transposition error": 1. A simple and common error of data entry when two digits in a number are reversed (transposed). When two adjacent digits are transposed the error will always be divisible by 9. For example: If 3,460 should be 3,640the difference is 180 (3,640-3,460=180) 180/9 = 20. 2. Similar errors with non-numerical data. For example ABC entered wrongly as ACB.