From 21 to 99, German says the small number first, then und, then the ten - all written as one word. So 21 is einundzwanzig, literally 'one-and-twenty'. The number 1 loses its -s here: eins alone, but ein- inside a compound.
Examples
- Ich bin einundzwanzig Jahre alt.
- I am twenty-one years old.
- Das kostet zweiundvierzig Euro.
- That costs forty-two euros.
- Meine Oma ist siebenundneunzig.
- My grandma is ninety-seven.
The mistake to avoid
Saying the tens first ("zwanzig-eins") - German always reverses the order and joins it into a single word.
Where this fits in
Numbers, days, time, German A1: Count, talk about days and months, give the time, and handle numbers in real situations.