by a computer program[^2], increasing speed billion-fold. Mathematically, results which can be explicitly computed using hand-held scientific calculator are members of so-called $\exp-\log$ (EL) numbers [@chow]. Above formulation has many advantages over set-theoretic or decimal string matching approach. It is well-posed, tractable, and can be either answered:\
a) positively,\
b) in terms of probability, or\
c) falsified.\
This depend on both maximum length of button sequence (code length, Kolmogorov complexity), as well as precision of the numerical result. One could anticipate, that for high-precision numbers (arbitrary precision in particular) and short code length identification must be unambiguous. For intermediate case (double precision, unspecified code length) we expect to provide some probability measure for identification. For low-accuracy numbers (e.g. of experimental or Monte Carlo origin) failure seems inevitable. Article is devoted to quantify above considerations. Certain statistical criteria are presented for practical number identification. Hopefully, this will convince researchers, that constant recognition problem can be solved practically. Instead of software used mainly for recreational mathematics and random guessing, it could become reliable tool for numerical analysis and computer algebra systems.

Article is organized as follows. In Sect. \[ELnumbers\] we discuss simplified computer language (in replacement for physical scientific calculator) used to 