This workflow is provided by default along with Simply CRM package. This is a good example to depict how fields within same record can be updated when workflow is executed. We are set to do the following calculation.

Forecast Amount is equal to Amount * Probability / 100

1. Opportunities is selected in Select Module dropdown. Fields in the record should be updated on every save; for that reason, workflow running condition is Every time the record is saved.

2. Click Save

3. The goal is to update all fields. No specific condition is required. Click Next

4. Click Add Task and select Update Fields. Provide Task Title; this is only for your reference. Click Add Field button; as a result, two fields will be displayed. One is target field other is source field. Select Forecast Amount from the dropdown.

Clicking on source field brings up a popup. You can define calculations in this popup. In the popup, as we are performing calculations, I will suggest you to select Expression from the first dropdown. This will give you the flexibility to select available fields from second dropdown and functions from the third. We only need to populate fields in this example.

From the use field dropdown, select Amount field, type in ( * ) from your keyboard, select Probability field, type in ( / ) from your keyboard and type in 100 from your keyboard. That makes it Amount * Probability / 100. Click Save to update your calculation.

5. Click Save

6. Click Finish