Relational operators (<, >, <=, >=) behave differently depending on operand types. When at least one operand is a number, both are coerced to numbers. When both operands are strings, comparison is lexicographic (character by character) — no number coercion occurs. This is why '10' > '9' is false (lexicographic: '1' < '9') but '10' > 9 is true (numeric: 10 > 9).