YOU SAID:

I think my banjo is on my seven year old birthday cake

INTO JAPANESE

私のバンジョーは私の7歳の誕生日のケーキの上にあると思う

BACK INTO ENGLISH

I think my banjo is on my 7th birthday cake

INTO JAPANESE

私のバンジョーは私の7番目の誕生日のケーキにあると思う

BACK INTO ENGLISH

I think my banjo is in my seventh birthday cake

INTO JAPANESE

私のバンジョーは私の7番目の誕生日ケーキに入っていると思う

BACK INTO ENGLISH

I think my banjo is in my 7th birthday cake

INTO JAPANESE

私のバンジョーは私の7番目の誕生日のケーキに入っていると思う

BACK INTO ENGLISH

I think my banjo is in my 7th birthday cake