Totally new to VBA and I need help

[Kazarak]

I am working on an workbook that serves as a character sheet in a table top RPG that I play. I am trying to find a way to code the hit point functions in VBA so that I can enter numbers in three different cells and have the entered numbers subtract or add to other cells and then clear the field for another entry. One for taking damage, one for getting healed, and one for gaining temp HP. I realize some of this may be information you don't need to know but I feel like explaining what I want to accomplish is helpful. the code I have come up with so far is this:

Sub HitPointFunction()
If Worksheets("Main").Range("M29").Value = 0 Then
Worksheets("Main").Range("M29").Value -Range("I28").Value
Else
Worksheets("Main").Range("M29").Value -Range("I28").Value

End If
End Sub

I am just getting started on the attempt at coding this and quickly ran into problems. This doesn't work. It throws up run-time error 438: Object doesn't support this property or method. I realize this is basic code but I am not experienced in this at all. I am simply trying to learn through Google. I don't think this works conceptually or at least not the way I am writing it. I can attach the workbook if that would help just let me know

 

[Norie]

Which cell are you trying to subtract from and which cell has the value you want to subtract?

If you wanted to subtract the value in I28 on the active sheet from the value in M29 on the sheet 'Main' this is how the code would look.

Sheets("Main").Range("M29").Value = Sheets("Main").Range("M29").Value - Range("I28").Value

 

[Kazarak]

This is one of the parts I would like to do. I am hoping for it to be conditional. I want the value in I28 to be subtracted from M29 only if M29 has a value. If M29 has no value I would like it to be subracted from M24. This is the basis of what I'd like to do for the most part. I appreciate your help with this.

 

[Norie]

For that, try this.

If Sheets("Main").Range("M29").Value > 0 Then
    Sheets("Main").Range("M29").Value = Sheets("Main").Range("M29").Value - Range("I28").Value
Else
    Sheets("Main").Range("M24").Value = Sheets("Main").Range("M24").Value - Range("I28").Value
End If