Addition

Produces a result by computing the numeric sum of its left and right operands. If the two operands are both expressions of type integer, then integral addition is performed and the result is of type integer. If the two operands are both of type decimal or both of type float, then floating-point addition is performed and the result type is the same as the operand type.

Subtraction

Produces a result by computing the numeric difference between the left and right operands by subtracting the value of the right operand from the left. If the two operands are both expressions of type integer, then integral subtraction is performed and the result is of type integer. If the two operands are both of type decimal or both of type float, then floating-point subtraction is performed and the result type is the same as the operand type.

String concatenation

Produces a result by adding two strings together. The result is a new string whose value is the value of the right operand, an expression of type string, appended to the value of the left operand, an expression of type string. The result type of the string concatenation operator is string.