Аннотация:Algorithm description is the basic unit in the AlgoWiki Open Encyclopedia of Algorithmic Features. However, computational algorithms are not objectives in and of themselves: they are needed to address problems encountered in various fields of science and industry. On the other hand, there are many practical problems that can be tackled using various methods. This warrants the introduction of another basic term that fits between the concepts of a problem and an algorithm. Also, any algorithm can have different implementations, whether related to a single computing platform or to different platforms. The “problem–method–algorithm–implementation” chain is the basis for describing any subject area in AlgoWiki. This paper describes the permitted freedom in describing such chains, which arises when studying the approaches to address various practical problems.