

사십 번 버스를 타세요.
[sasip pʌn pʌsɯlɯl tʰasejo.]
Take bus number 40.
회사까지 사십 분쯤 걸려요.
[hwesak͈at͡ɕi sasip punt͈͡ɕɯm kʌlljʌjo.]
It takes about forty minutes to get to work.
오늘 사십 페이지까지 읽었어요.
[onɯl sasip pʰeit͡ɕik͈at͡ɕi ilkʌs͈ʌjo.]
I read up to page 40 today.
"사십" 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.