A new combinatorial optimization problem, the Bandpass problem, was defined in Bell and Babayev (2004) . Recently, this problem was investigated in detail in Babayev et al. (2009) . In this paper, we first present some new mathematical models of the Bandpass problem. Then related to this problem, we introduce a software called OrderMatic which is very useful for teaching permutations. (C) 2010 Elsevier Ltd. All rights reserved.