Here is how to count from 1 to 100 in Korean for your Taekwondo classes:
1 - hana
2 - tul
3 - set
4 - net
5 - tasot
6 - yosot
7 - ilgop
8 - yodolp
9 - ahop
10 - yol
11 - yol-hana
12 - yol-tul
13 - yol-set
14 - yol-net
15 - yol-tasot
16 - yol-yosot
17 - yol-ilgop
18 - yol-yodolp
19 - yol-ahop
20 - sumul
30 - sorun
40 - mahun
50 - shween
60 - yesun
70 - irun
80 - yodun
90 - ahun