Private Sub cmdGo_Click()
Dim value As Single
Dim rounded As Integer
Dim truncated As Integer

    value = CSng(txtValue.Text)
    rounded = CInt(value)
    truncated = Int(value)
    lblRounded.Caption = Format$(rounded)
    lblTruncated.Caption = Format$(truncated)
End Sub

Note also that CInt rounds to the nearest even integer for integers plus one half. For example, CInt(16.5) = 16 and CInt(15.5) = 16. It would be better if it always rounded these values up (like most people do) or down, or even if it rounded towards zero. That would make each interval cover the "same" number of values.

The reasoning is that the value could go either way. Rounding to the nearest even value makes it round up half the time and down half the time.