
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
Old Man Wang, in order to sign a purchase and sale contract with a customer, estimated the total number of fish in his pond. The first time, he caught 100 fish, marked each one, and released them back into the water. After they were fully mixed with the other fish, he caught another 100 fish, among which there were 2 marked fish. The estimated number of fish in Old Man Wang's pond is approximately ____ fish.

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