Try this 
result 1:
Result 1 = CDbl(row("A").ToString.Replace("₺", "").Replace(",", ".")) - CDbl(row("A_dbv").ToString.Replace(",", "."))
result 2:
Result 2 = CDbl(row("B").ToString.Replace("₺", "").Replace(",", ".")) - CDbl(row("A_dbv").ToString.Replace(",", ".")) - CDbl(row("B_dbv").ToString.Replace(",", "."))
result 3:
Result 3 = CDbl(row("C").ToString.Replace("₺", "").Replace(",", ".")) - CDbl(row("A_dbv").ToString.Replace(",", ".")) - CDbl(row("C_dbv").ToString.Replace(",", "."))
Here’s a complete example
<UiPath.Workflow>
<Sequence>
<Excel Application Scope Path="path\to\your\file.xlsx">
<Read Range SheetName="Sheet1" Range="" Output="dtData"/>
<For Each Row In DataTable>
<Assign>
<Variable>[Result 1]</Variable>
<Value>CDbl(row("A").ToString.Replace("₺", "").Replace(",", ".")) - CDbl(row("A_dbv").ToString.Replace(",", "."))</Value>
</Assign>
<Assign>
<Variable>[Result 2]</Variable>
<Value>CDbl(row("B").ToString.Replace("₺", "").Replace(",", ".")) - CDbl(row("A_dbv").ToString.Replace(",", ".")) - CDbl(row("B_dbv").ToString.Replace(",", "."))</Value>
</Assign>
<Assign>
<Variable>[Result 3]</Variable>
<Value>CDbl(row("C").ToString.Replace("₺", "").Replace(",", ".")) - CDbl(row("A_dbv").ToString.Replace(",", ".")) - CDbl(row("C_dbv").ToString.Replace(",", "."))</Value>
</Assign>
<Write Cell SheetName="Sheet1" Cell="G" Value="[Result 1]" />
<Write Cell SheetName="Sheet1" Cell="H" Value="[Result 2]" />
<Write Cell SheetName="Sheet1" Cell="I" Value="[Result 3]" />
</For Each Row>
<Save Workbook/>
</Excel Application Scope>
</Sequence>
</UiPath.Workflow>
This example assumes that:
- The columns are named exactly as in your screenshots.
- The data starts from row 2 (row 1 contains headers).
Make sure to replace path\to\your\file.xlsx with the actual path to your Excel file.
Feel free to adapt the variable names and cell references as necessary.