High Quality Content by WIKIPEDIA articles! In mathematics, various typographical forms of brackets are frequently used in mathematical notation such as parentheses ( ), square brackets , curly brackets { }, and angle brackets . In the typical use, a mathematical expression is enclosed between an "opening bracket" and a matching "closing bracket". Generally such bracketing denotes some form of grouping: in evaluating an expression containing a bracketed sub-expression, the operators in the sub-expression take precedence over those surrounding it. Additionally, there are several specific uses and meanings for the various brackets.