Operators are functions that represent basic operations on values: addition, subtraction, etc. They are frequently used and are core parts of the Perl programming language. They are really just functions that take arguments. For instance, + is the operator that adds two numbers, like so:
3 + 4;
Operators typically have one, two, or three operands; in the example just given, there are two operands 3 and 4.
Operators can appear before, between, or after their operands. For example, the plus operator + appears between its operands.