Absolutely, there are ways to use the SUM function in Excel to add only positive or negative values! Here are two common methods:

Method 1: Using SUMIF

The SUMIF function allows you to sum a range of cells based on a specific criterion.

1. Identify your range: Specify the range of cells containing the values you want to sum (e.g., A1:A10).
2. Set the criteria: Define the condition for selecting positive or negative values.
- For positive values, use ">0" (without quotes).
- For negative values, use "<0" (without quotes).
3. Target range (optional): In most cases, you can leave this blank as it defaults to the range you specified in step 1.

Example:

To sum only the positive values in cells A1:A10, use the following formula in another cell (e.g., B11):

`=SUMIF(A1:A10, ">0")`

This formula will add all the positive values in A1:A10 and display the result in B11.

Method 2: Using SUMIFS (Excel 365 and later)

SUMIFS offers more flexibility, allowing you to sum based on multiple criteria. It's available in Excel 365 and later versions.

1. Identify your range: Specify the range of cells containing the values (e.g., A1:A10).
2. Set the first criteria: Define the condition for positive or negative values as in method 1 (">0" or "<0").
3. Additional criteria (optional): SUMIFS allows adding more criteria for further filtering.

Example:

To sum only the positive values greater than 5 in cells A1:A10 (assuming Excel 365), use:

`=SUMIFS(A1:A10, ">0", A1:A10, ">5")`

This formula will add all positive values in A1:A10 that are also greater than 5.

Both methods achieve the same goal of summing positive or negative values. Choose the one that best suits your Excel version and specific needs.