When creating a Calculated Column in a BidTable, you are unable to select one of your Vendor Columns as a variable to be part of the calculation.
The Vendor Column you're selecting might have the Format set to Text instead of Number. Calculated Columns can only accept columns formatted as numbers.
1. Delete the Vendor Column that is formatted as Text by clicking the trashcan icon underneath the title of the column.
2. Create a new Vendor Column by clicking Add Column -> Vendor Column at the top of the page.
3. In the Add Vendor Column modal that pops up, click on the dropdown menu under Format and select the Number option. Remember to enter in the name of the column and click Save.
You should now be able to select the column as a variable when creating the Formula for your Calculated Column. For more info, please see our Calculated BidTable Columns page.