# SUM

The SUM function calculates the sum of a series of numbers.

- Syntax:
- SUM ( series-number-expression )
- Meaning:
- SUM ( series_to_sum )
- Returns:
- A single number

SUM returns
the sum of all members in `series_to_sum`.

## Examples

- SUM ( Quantity:LineItem )
This example calculates the sum of all the

**Quantity**objects of**LineItem**.