A problem sequence is presented developing the basic properties of the set of natural numbers (including associativity and commutativity of addition and multiplication, among others) from the Peano axioms, with the last portion using von Neumann's construction to provide a model satisfying these axioms. This sequence is appropriate for mathematically inclined students in their first or second years, and has regularly required about a week of class time. The sequence could be included as one unit within any of several appropriate courses, and could be an ideal "trial size" first attempt at guiding inquiry-based learning in the tradition of R.L. Moore.