Practical guide and verification
What the remainder means
For integer division, dividend = divisor × quotient + remainder. That identity is the quickest way to check a result.
Negative numbers
Programming languages and mathematical conventions can differ in how they define quotient and remainder for negative inputs. If negatives matter, verify the convention required by your application rather than assuming every `%` operator behaves the same.
Decimal inputs
A classic integer remainder is different from a floating-point remainder. Decide whether you need Euclidean division, modulo arithmetic, or a programming-language remainder before interpreting the output.