**Arithmetic Operators**

An expression may contain arithmetic operators, which determine how variables and constants are manipulated. For example, the operator "+" indicates that two items should be added together.
The division, subtraction, and multiplication operators can only be used with numeric operands. The operands can be variables, constants, or subexpressions. A formula error occurs if:

- the result of subtraction is too large a negative number

- the result of multiplication is too large

- the second operand of a division evaluates to zero

In both cases, 'too large' here is determined by the normal limits in the ORACLE database.
The addition operator can be used with numeric or text operands. If the result is greater than 240 characters, a formula error occurs.

Notice that you enclose text constants in single forward quotes only ('), not double quotes ("). For example, the statements:

` string1 = 'will '`

` result_string = 'Pigs ' + string1 + 'fly'`

set the local variable `result_string` to 'Pigs will fly'.