1. He has four balls. One is white, another is blue, another is green, and the other is yellow.

2. He has four balls. One is white, another is blue, a third is green, and the other is yellow.

3. He has four balls. One is white, another is blue, a third is green, and the fourth is yellow.

4. He has four balls. One is white, a second is blue, a third is green, and the other is yellow.

5. He has four balls. One is white, a second is blue, another is green, and the fourth is yellow.
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Are they all grammatical? Which ones are commonly used?

All are grammatically correct.

#3 is probably most used, but there are variations.

All five sentences are grammatical, but they have slight variations in terms of structure and emphasis. Here's an explanation for each sentence:

1. This sentence uses "another" to refer to the second ball. It is grammatical and commonly used.

2. This sentence uses "a third" instead of "another" to refer to the third ball. It is also grammatical and commonly used.

3. This sentence uses "the fourth" instead of "another" to refer to the fourth ball. It is grammatical and commonly used.

4. This sentence uses "a second" instead of "another" to refer to the second ball. It is grammatical, but it might sound less common or slightly less natural compared to the previous sentences.

5. This sentence uses "another" to refer to the second ball, similar to the first sentence, but it uses "fourth" instead of "one of them." It is grammatical and commonly used.

Overall, all of these sentences are correct and can be used depending on the specific context and style you prefer.