Korean uses two systems of numbering; the first form is the native Korean, and is used mainly for counting items (e.g. push ups). The second form originates from Chinese, and is mainly used where English would use the ordinal (first, second, etc.), and takes a modifying noun. Hence, Korean for first dan would be il dan, two direction is i-bang, three-step sparring is sambo matsogi, and so forth. However, this is a necessary simplification: for more reading, try Korean Numerals on Wikipaedia.