Convert these cardinal numbers into ordinal numbers: 1, 2, 3, 5, 9, 12, 15, 20, 40, 50.

Here are the completed ordinal numbers:

1. $1^{st}$ $\rightarrow$ first
2. $2^{nd}$ $\rightarrow$ second
3. $3^{rd}$ $\rightarrow$ third
4. $5^{th}$ $\rightarrow$ fifth
5. $9^{th}$ $\rightarrow$ ninth
6. $12^{th}$ $\rightarrow$ twelfth
7. $15^{th}$ $\rightarrow$ fifteenth
8. $20^{th}$ $\rightarrow$ twentieth
9. $40^{th}$ $\rightarrow$ fortieth
10. $50^{th}$ $\rightarrow$ fiftieth