: Provides free online tests and simulators specifically designed for 6th-grade students to prepare for exams and Olympiads.
For online 6th-grade mathematics tests (тесты по математике в 6 классе онлайн), there are several high-quality resources ranging from standard curriculum practice to competitive Olympiad training. Online Testing Platforms (Russian Curriculum)
Тесты по математике за 6 класс онлайн
If you are looking for more rigorous "Russian Math" style problems or specific papers for download:
: Offers a wide variety of user-generated and formal tests, including comprehensive final exams like the 10-question final test based on Nikolsky’s textbook.