The three-digit integer $63\underline{\hphantom{0}}$ is a multiple of 3. What is the greatest possible difference between two of the possibilities for the units digit?
Question:
The three-digit integer $63\underline{\hphantom{0}}$ is a multiple of 3. What is the greatest possible difference between two of the possibilities for the units digit?
Answer:
Let's think step by step.

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The three-digit integer $63\underline{\hphantom{0}}$ is a multiple of 3. What is the greatest possible difference between two of the possibilities for the units digit?
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