  The article is devoted to modeling of the nega-$\tilde Q$-representation of
real numbers. The representation is a generalization of representation by
alternating Cantor series and positive $\tilde Q$-representation is a
generalization of representation of real numbers by the positive Cantor series.
Analytic and geometric approach are used for modeling of nega-$\tilde
Q$-representation. Advantages and disadvantages of these approaches are
investigated, the representation is modeled.
  The investigation was represented in seminar on fractal analysis of Institute
of Mathematics of the National Academy of Sciences of Ukraine on, October 30,
2014 (http://www.imath.kiev.ua/events/index.php?seminarId=21&archiv=1) and
International Conference "Probability, Reliability and Stochastic
Optimization", Kyiv, April 7-10, 2015.
