第一百是hundredth還是onehundredth

是one hundredth，例如

Next week is the one hundredth anniversary of the Paris Air Show， the biggest in the world.下週是巴黎航空航展100週年紀念日，目前世界上規模最大的航展。

Well， sir， I hope to have the privilege of interviewing you on your one hundredth birthday.

先生，我希望我能榮幸地在您一百歲大壽時再來採訪您。