실수 (Error) refers to a mistake or an incorrect action that deviates from what is intended or expected. Errors can occur in various contexts, such as in mathematics, where a calculation may be wrong, or in communication, where a misunderstanding can lead to confusion. Recognizing and correcting errors is essential for learning and improvement. In many fields, including science, engineering, and software development, errors are analyzed to understand their causes and prevent future occurrences. Tools and methods, such as error analysis and quality control, are employed to identify and minimize errors, ensuring better outcomes and increased efficiency.