

Билет стоит пятьдесят рублей.
The ticket costs fifty rubles.
Папе в мае будет пятьдесят.
Dad will be fifty in May.
Ты прочитал пятьдесят страниц?
Did you read fifty pages?
"пятьдесят" is in the lesson "Big numbers" (Level 4), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,380 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.