Declension of Russian Cardinal Numerals (with audio)
https://learnrussianstepbystep.com › ...When numbers 50, 60, 70, 80, 200, 300, 400, 500, 600, 700, 800 and 900 are declined, both their parts (пять-десят, пять-сот) change endings. 50, 80, 200, 500.