Numerical codes are sequences of numbers used to represent information in a simplified form. They can be found in various fields, such as computer programming, where they help in data processing, or in barcodes, which store product information for easy scanning at checkout. These codes can also be used for security purposes, like in PINs (Personal Identification Numbers) that protect access to accounts. By using numerical codes, complex information can be communicated quickly and efficiently, making them essential in modern technology and everyday life.