VBA activate Sheet in Excel

[McM_]

Hello
I know this is a beginner problem, but is there anyone who can help me with the information below?
How to activate VBA that launches a formula from the Sheet, and that formula to run C3:C100, without the need to launch with F5?
In the end, I managed to display the date under certain conditions, without needing to activate it with F5.
I can't find how to activate the formulas without F5.
Please excuse the technical terms.
Thank you !

Sub Macrocomandã5()    Range("C2:C8").Select    ActiveCell.FormulaR1C1 = "=IF(RC[-2]>0,(RC[-2]+RC[-1]),"""")"    Range("C2:C8").Select    Range("C3").Activate    End SubPrivate Sub worksheet_Change(ByVal Target As Range)Dim ws As WorksheetIf Target.Column = 8 ThenRange("I" & Target.Row) = NowEnd IfIf Target.Column = 14 ThenRange("M2:M" & Target.Row) = Range("L2")End IfEnd Sub

 

[McM_]

From the example in the table, the macro is activated only on C3.
I need it to be activated on the whole C column

 

[McM_]

I come with clarifications.
Now, if cell B3 is completed, trigger the macro with the formula and the result is in C3.
I need if B4 is completed, the formula should calculate in C4, B4-A4;
Completed B5, B5-A5, and so on for the rows that meet the condition in the formula.
Thank you for your time!

Sub Formula()

    Range("C3:C8").Select
    ActiveCell.FormulaR1C1 = "=IF(RC[-2]>0,(RC[-2]+RC[-1]),"""")"
    Range("C3:C8").Select
    Range("C3").Activate
    
End Sub

VBA.xlsm
	A	B	C	D	E
2
3	1	3	2
4	3	4		didn't work
5	5	9		didn't work
6	5	6		didn't work
7
8
9
10
11
12
Foaie1

Cell Formulas
Range	Formula
C3,D11,C8:C9	C3	=IF(ISNUMBER(B3),B3-A3,"")

 

[rlv01]

If I understood what you just posted then perhaps:

Book2
	A	B	C
2	Col A	Col B	Result
3	1	3	4
4	3	4	7
5	5	9	14
6	5	6	11
Sheet1

Cell Formulas
Range	Formula
C3:C6	C3	=IF(A3>0,(A3+B3),"")

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim rng As Range

    With Me
        Set rng = .Range("A3:B" & .Range("A" & .Rows.Count).End(xlUp).Row)
    End With

    If Not Application.Intersect(rng, Target) Is Nothing Then
        With rng.Offset(0, 2).Resize(, 1)
            .FormulaR1C1 = "=IF(RC[-2]>0,(RC[-2]+RC[-1]),"""")"
        End With
    End If
End Sub

 

[McM_]

rlv 01
Thanks for your help. It works.

 

[rlv01]

Glad I could help.