# op:numeric-add - XPath XQuery Reference

Returns the arithmetic sum of its operands: ($arg1 + $arg2).Defines the semantics of the "+" operator when
         applied to two numeric valuesGeneral rules: see . For xs:float or xs:double values, if one of the operands is a
            zero or a finite number and the other is INF or -INF,
               INF or -INF is returned. If both operands are
               INF, INF is returned. If both operands are
               -INF, -INF is returned. If one of the operands is
               INF and the other is -INF, NaN is
            returned.