' FB 1.05.0 Win64

Dim s As String = "123456789"
Dim As Integer n = 3, m = 4
Print Mid(s, n, m)
Print Mid(s, n)
Print Left(s, Len(s) - 1)
'start from "5" say
Print Mid(s, Instr(s, "5"), m)
' start from "12" say
Print Mid(s, Instr(s, "12"), m)
Sleep