The necessity of quantitative estimation of non-failure operation of complex technical structures at the beginning of the 60s XX centuries stimulated the so-called logic and probabilistic calculus (LPC) which is a part of the mathematics treating rules of calculus and operating with statements of two-valued logic. LPC is based on the logic algebra and rules of replacement of logical arguments in functions of the logic algebra (PAL) by probabilities of their being true and rules of replacement of the logic operations by the arithmetic ones.