# sum (List, optional Startindex, optional endindex)

This function is designed to return the sum of a list of values or the sum of a range in a list of values.

**sum(List) → number**

This function designed to calculate the sum of a list of numeric values or elements. **sum(List of list, start index, end index) → number**

This function designed to calculate the sum of the values between given indices in a list of numeric values or elements.

**Example:**

```xml
<O N="sumObject1" T="Project" Category="Functions" TransAlignRule="1">
    <!-- created by ParamML Examples on 8/22/2023 -->
    <P N="List1" V="[0,1,2,3,4,5,6,7,8,9]" />
    <P N="sumList" V="sum(List1)" />
    <P N="sumRangeList" V="sum(List1,5,6)" />
</O>
```

![](https://openbrim.atlassian.net/wiki/download/attachments/2167767174/image-20230822-113104.png?api=v2) As demonstrated, sumList returns the total of List1 while sumRangeList returns the sum of values between 5-6th indices of List1. To view this example in the library, see (<https://openbrim.org/app/?incubator=1&author=ParamML_Examples_OpenBrIM+Platform&obj=objidqokstqo0bi25myjlp2zo2> )