Riddle: Odd One Out?!

Question:

Riddle: Odd One Out?

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The words one, five, seven, and nine have something in common.

The word three doesn't belong to that group.

What is that similarity?

Answers: one, five, seven and nine have at least one consonant among the last two letters
This isn't true for three the first letter is curved???? uhh
they all hate three.
=/ two letter e's appear next to each other in the number three but not in the other? um they are all numbers? kay im just stating the obvious but.....
one, five, seven, and nine, are the odd numbers less than ten without any repeating consonants
seven doesnt belong because it is 2 syllables
dont know the last question though one, five, seven and nine - alternate between vowels and consonants, but three doesn't do that, with the consonants at the start and the vowels at the ends

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