Before you even said the word 'karate' I knew you must have learned counting from a martial arts class . I used to study Kendo for 2 years, and they counted the same way.. however, the way its done in martial arts is not the same way you count normally (especially regarding numbers 20 and above). Don't use that method of counting in regular speech or writing.
The 'standard' way for numbers would be...
1. Ichi
2. Ni
3. San
4. Yon/Shi
5. Go
6. Roku
7. Nana/Shichi
8. Hachi
9. Kyuu
10. Jyuu
11. Jyuu ichi
12. Jyuu ni
13. Jyuu san
...and so on for the teens
20. Ni jyuu
21. Ni jyuu ichi
22. Ni jyuu ni
23. Ni jyuu san
...etc