Get new result on each repeat

Sub lab1_5()
Dim displayText As String
Do

    number = InputBox("Write number: ")

    For i = 1 To 9
        number = number * 2
        displayText = displayText & " " & number
    Next i
    MsgBox displayText
    Dim answer As VbMsgBoxResult
    answer = MsgBox("KONIEC" & vbNewLine & "Chcesz spróbować jeszcze raz?", vbYesNo)
Loop While (answer = vbYes)
End Sub

If I write for example 2 it shows 2 4 8 16 etc.
After clicking yes and writing another number i have previous (2 4 8 etc.) and new numbers.

How can I have only new numbers?

You need to reset displayText to an empty string at the start of the do loop.

Sub lab1_5()
Dim displayText As String
Do

Number = InputBox("Write number: ")
displayText = "" '<--- this line here
For i = 1 To 9
    
    Number = Number * 2
    displayText = displayText & " " & Number

Next i
MsgBox displayText
Dim answer As VbMsgBoxResult
    answer = MsgBox("KONIEC" & vbNewLine & "Chcesz spróbowac jeszcze raz?", vbYesNo)
Loop While (answer = vbYes)
End Sub