# Addition Assignment Operator (+=)

Adds the value of an expression to the value of a variable and assigns the result to the variable.

*result* **+=** *expression*

#### Arguments

*result*
- Any variable.
*expression*
- Any expression.

#### Remarks

Using this operator is exactly the same as specifying:

result = result + expression

The underlying subtype of the expressions determines the behavior of the **+=** operator.

If |
Then |

Both expressions are numeric or Boolean |
Add |

Both expressions are strings |
Concatenate |

One expression is numeric and the other is a string |
Concatenate |

#### Requirements

Version 1

#### See Also

+ Operator | Operator Precedence | Operator Summary