Write integer in excel with decimal

Hi Guys,

I am trying to write a number to excel, in a cell that that is summed by a formula in another cell below.

My problem is that excel recognices the inserted value as text, and the number is therefore not included in the sum formula.

I have tried using a solution I found here with: System.Text.RegularExpressions.Regex.Replace(Value,"[^,1-9]",""): It does work, but it also removes my decimal point, which of course makes my sum way too high.

Anybody has a solution?