A new anthropological approach to ancient Russian cultural sources has gained prominence lately in studies of mathematical knowledge in early Rus. It has been found, that calculation skills dealing with letter-numbers and the abacus were widespread in the life of early Russians, especially among literate population groups - clergy, copyists, middle and high officials, military governors, artisans, etc. In particular, comparisons between real-life situations mentioned in books of mathematical problems with the same situations as described in non-mathematical texts (e.g. livestock prices) reveals both the didactic nature of the mathematical literature and its intended audience (local and regional officials). Such a «multidimensional methodology of studying various layers of historical process» (in V. Zh. Kelle's terminology) helps reconstruct the cultural meanings of early Russian «everyday» mathematics.