Correct spelling, explanation: the word hundred is a numeral used to represent the number 100. This form comes from Middle English hundred and from Old English hundred. As you can see, it hasn’t changed until now. You can’t spell this word as hundered, because the additional -e vowel is completely unnecessary.

Definition of hundred:
numeral, the number equivalent to the product of ten and ten; ten more than ninety; 100
The museum proudly displayed a priceless collection of rare artifacts, including a hundred-year-old handwritten manuscript.
The construction project required several hundred workers to complete within the tight deadline, demonstrating the scale and complexity of the undertaking.

Collocations with hundred:
Some most commonly used collocations include:
1. A hundred times: used to emphasize repetition or frequency.
She practiced the piano a hundred times before the recital.
2. A hundred percent: referring to completeness or certainty.
I am a hundred percent sure that I locked the door before leaving.
3. A hundred years: denoting a long period of time.
The ancient ruins have been standing for over a hundred years.
4. Several hundred: indicating an approximate quantity.
The concert attracted several hundred attendees.

Incorrect spelling, explanation: the word hundered doesn’t exist in any dictionary – it’s just a plain spelling mistake. It may occur due to carelessness or pronunciation issues. We should remember that the one and only correct form of this numeral is hundred and this version matches with the etymology.