Sub Макрос1()
    Application.ScreenUpdating = False
    On Error GoTo Err0
    
    Sheets("Лист1").Select
    
    For i =  2  To  31  ' номера строк
        a0 = Range("A" & CStr(i)).Value
        If Val(a0) >  10  Then
            Range("B" & CStr(i)).Value = a0 *  10 
            Range("B" & CStr(i)).Font.ColorIndex =  5  ' синий
        Else
            Range("B" & CStr(i)).Value = ""
        End If
    Next
    
    MsgBox "ГОТОВО"
    Application.ScreenUpdating = True
    
    Exit Sub
Err0:
    Application.ScreenUpdating = True
    MsgBox Err.Description
End Sub