The article presents a fragment of academic rules, namely those for spelling unstressed vowels in noun endings. Tables and teaching materials accompany the rules. This section of orthography is well-studied and described in both scientific and methodological literature. The provided characterisation is generalising: it systematically presents all orthographically significant types of noun declensions. The main rule formulation does not result in the usual vicious cycle, i. e. when the ending of the original form determines declension type (words ending with -a(-ya), words ending with -o(-ye)), and the ending of the motivating word is determined by the declension type (lake/ozero as window/ okno). The rules address all groups of words and individual lexemes that diverge from standard paradigms and present spelling difficulties. These include bolgarin – bolgary/a Bulgarian – Bulgarians, but anglichanin – anglichane/an Englishman – the English; Pushkin – Pushkinym/Pushkin – by Pushkin, but Chaplin – Chaplinom/Chaplin – by Chaplin; Sofia – o Sofii/Sofia – about Sofia, but Liya – o Lie/Leah – about Leah, Viy – o Vie/Viy – about Vii; j-stem words (Maya)), as well as grammatical variants (usishcha and usishchi/a very big moustache). We also mention individual words with stressed endings which do not correspond to this declension type (put’/path, kiy/cue). The rules prevent errors in dividing word forms into morphemes incorrectly. Such mistakes are common in reference and educational literature. One note discusses the problem of differentiating noun forms ending with -ie, -ii from derivative prepositions and lexicalised (adverbial) prepositional-case combinations associated with them. Their pronunciation coincides with that of prepositions (v zaklyuchenii soderzhitsya oshibka/there is an error in the conclusion – v zaklyuchenie seminara blagodaryu vsekh uchastnikov/in conclusion of the seminar, I thank all participants, skazal v zaklyuchenie/in conclusion, he said). Teaching materials enable educators to consistently form the skills necessary to correctly spell prepositions ending with -ie, -ii, as well as adverbial combinations and prepositional noun phrases associated with them. A sufficient number of examples, their grouping and arrangement enable learners to observe the semantic, syntactic, spelling differences of prepositions, adverbial combinations, and nouns. The materials permit wide variation in the volume and complexity of assignments. This allows teachers to adapt them focusing on the age and the preparation level of learners.