native Korean numbers with counting units

https://www.youtube.com/watch?v=cis3C_I9pA4

 

When you just count numbers 

1하나 2둘 3셋 4넷 5다섯 6여섯 7일곱 8여덟 9아홉 10열

---

However when you count numbers with counting units like bottle, cup, etc 

1~4 change like this

1한 2두 3세 4네 

---

      for examples

커피 coffee	한 one	잔 cup
주스 juice	두 two	병 bottle
밥 rice	세 three	그릇 bowl
사과 apple	네 four	개 stuff, thing
물 water	한 one	컵 cup

you can use 잔/컵 both when you count like water, 잔 is more often use for hot drink because 잔 means teacup, and it is including saucer.

5~10 not change. 

What do you want to practice more?