
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
A four-digit number has $a$ as the digit in the thousand's place, $b$ as the digit in the hundred's place, $c$ as the digit in the ten's place, and $d$ as the digit in the unit's place. This four-digit number is __________. (Hint: Express it using an expression that includes letters, with each place value having a base of 10)

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