Display Grades using select case

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim per As Single

        per = TextBox1.Text

        Select Case per

            Case 0 To 49

                Label4.Text = "Fail"

            Case 50 To 59

                Label4.Text = "D grade"

            Case 60 To 69

                Label4.Text = "C Grade"

            Case 70 To 79

                Label4.Text = "B Grade"

            Case 80 To 89

                Label4.Text = "B+ Grade"

            Case 90 To 95

                Label4.Text = "A Grade"

            Case 95 To 100

                Label4.Text = "A+ Grade"

            Case Else

                Label4.Text = "Please enter correct percentage"

        End Select

    End Sub