Option Explicit
Sub ChonSoNgau()
 Dim Rng As Range, sRng As Range
 Dim Tmp As Integer, Dm As Long
 Set Rng = [B3].Resize(10, 10)
 Rng.Interior.ColorIndex = 2
 Randomize
 Do
    Dm = Dm + 1
    Tmp = 100 * Rnd() \ 1
    Set sRng = Rng.Find(Tmp, , xlFormulas, xlWhole)
    If Not sRng Is Nothing Then
        sRng.Interior.ColorIndex = 38
        [B1].Value = "Só Làn: ":    [C1].Value = Dm
        Exit Do
    End If
 Loop
End Sub