Heres a clean way:

Dim isIn
Dim opt
Dim ok

ok = false
isIn = "100"

opt=Split("0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19")

for i = Lbound(opt) to Ubound(opt)
    if opt(i) = isIn then
        ok = true
    end if
next

MsgBox "Value found " & ok
Wscript.Quit