just trying to insert code to a cell in vba and not in cell on spreadsheet as i would like to change the value and have it automatically calculated. formula i would like is =b4*b3, my code is not working

Sub insertformula()
Dim A As Range
Dim B As Range


Set A = Range("B4")
Set B = Range("B3")


B.Value = B.Value * A.Value

End Sub