The ternary number system is a base-3 numeral system that uses three digits: 0, 1, and 2. Unlike the more common decimal system, which is base-10 and uses ten digits, the ternary system represents numbers using combinations of these three digits. Each position in a ternary number represents a power of 3, similar to how each position in a decimal number represents a power of 10. Ternary numbers can be useful in various fields, including computer science and mathematics. They can simplify certain calculations and algorithms, particularly in ternary logic, which is a form of logic that incorporates three truth values instead of the usual two.