Change sign to specific row in column when creating a PowerQuery/Power BI sheet

Hi.

i have this report that shows sales values and it sometimes includes negative values due to credits given for different reasons.

When creating a Power BI visualisation, I have managed to separate the groups I want to count and the last step is for me to "add back" things that are deducted as part of the table.

Whilst I can select the "Claim Credit" (which is what I need to add), this is negative on the column and I don't know how to change for that specific row to be a positive when doing the sum. I can do it in Excel with Sumif adding a "-" at the start but I don't know how to do it on PowerBI.

Thanks.

Thank you, I'll try that now