
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Xiaoming's original phone number was a six-digit number. During the first upgrade, the digit 8 was added between the first and second digits, resulting in a seven-digit number. In the second upgrade, the digit 2 was added in front of the first digit, making it an eight-digit number. Xiaoming discovered that the eight-digit number after the two upgrades is exactly 81 times the original six-digit number. What was Xiaoming's original phone number?

Present the answer in LaTex format: \boxed{Your answer}
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