00573naa#a2200181#i#450# EN\INFRA-M\bibl\7054 20260110112519.6 1998-0728 20150817b2015####ek#y0engy0150####ca RUS RU Continuity in Training Primary School Students and Fifth- and Sixth-Graders on How to Solve Mathematical Problems Journal article Moscow INFRA-M Academic Publishing LLC. 2015 10 с. Journal article local Burlakova T. Tselishcheva Irina naukaru.ru