First select the range that you want to verify, and later run this macro:
Code:
Sub SelectLessthan100()
Dim c As Range, R As Range
For Each c In Selection
If c < 100 Then
If R Is Nothing Then Set R = c Else Set R = Union(R, c)
End If
Next c
R.Select
Set R = Nothing: Set c = Nothing
End Sub
I don't know any method without VBA for make selection with logic conditions instead equals (for example: equals to 100 you could do with Find and Replace).
You can use a Third-Party Add-in like Kutools or something like this... but those add-ins were programmed by VBA.