Numeric prefixes are words that are added to the beginning of a number to indicate its magnitude. The most common numeric prefixes are octa (8) and TRI (3). Octa is used to denote 8 times the base unit, while TRI is used to denote 3 times the base unit. For example, an octal number is 8 times the base number, while a trinary number is 3 times the base number. Numeric prefixes are commonly used in mathematics, engineering, and computing.