What does the '%' operator represent in programming languages?

In most programming languages, the % symbol is the modulus operator. It divides one number by another and returns the remainder of that division rather than the quotient. For example, \( 10 \% 3 \) evaluates to \( 1 \), because \( 10 \) divided by \( 3 \) leaves a remainder of \( 1 \).

This operator is commonly used to check divisibility, for example testing whether a number is even by checking whether \( n \% 2 \) equals \( 0 \), or to keep a value cycling within a fixed range, such as wrapping around the hours on a clock. It is not the assignment operator, which is usually written as = and stores a value in a variable; it is not concatenation, which joins pieces of text together and is usually written with + or a dedicated operator; and it is not exponentiation, which raises a number to a power and is usually written as ** or ^.

Examination reminder: the modulus operator returns a remainder, not a quotient; confusing it with ordinary division (/) is the most common mistake.