300th or three hundredth.
Third (or 3rd) is the ordinal form of three.
60thSixtieth
The ordinal number is 18th or eighteenth. The word form is eighteen.
43rdForty-third
Third
Ninety-first or 91st
The number 31 in ordinal form is 31st or thirty-first.
8th, spelling: eighth
The ordinal number for 26 is 26th in digits. Spelled out, it's twenty-sixth.
Eighth and 8th
51stFifty-first