Incorrect spelling

fifthteen

Incorrect spelling, explanation: this spelling is incorrect because we add the suffix -teen to the cardinal, not ordinal numbers. Therefore the correct spelling is fifteen (although the number we add the suffix to is spelled five, the second f in fifteen is not voiced, because there is an unvoiced consonant following directly).


Correct spelling

fifteen

Correct spelling, explanation: the correct form of this cardinal number is fifteen. It might be confusing that five became fif after adding the suffix, however, the word five used to be, originally, fif. The second f in the word became voiced with time. In the word fifteen the f wasn’t voiced, because it is followed by unvoiced consonant t. fifthteen is incorrect because the suffix -teen is added to cardinal numbers, not ordinal ones.

Definition of fifteen:
numeral, between fourteen and sixteen
She got a beautiful bouquet of fifteen tulips from her husband for their 1st anniversary.
Betty is only fifteen but she has a part-time job already.


Incorrect spelling

fifthten

Incorrect spelling

Incorrect spelling

fiftyn

Incorrect spelling

Incorrect spelling

fiftin

Incorrect spelling

Incorrect spelling

fiveteen

Incorrect spelling

Incorrect spelling

fiften

Incorrect spelling

Incorrect spelling

fivteen

Incorrect spelling

Incorrect spelling

fiftheen

Incorrect spelling