Final answer:
A number can be classified as a repeating decimal if it has a decimal part that repeats. The numbers 0, 5.55, and 9 can be classified as repeating decimals.
Step-by-step explanation:
A repeating decimal is a decimal number that has a pattern of digits that repeats indefinitely. A number can be classified as a repeating decimal if it has a decimal part that repeats. In this case, the numbers that can be classified as repeating decimals are 0, 5.55, and 9.
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