
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
In recent years, 5G has been developing rapidly worldwide, and China has become a major driver in the construction of infrastructure, technology, and applications in this field. As of the end of March 2021, China has built approximately 819,000 5G base stations, accounting for over 70% of the global total. The number 819,000 can be expressed in scientific notation as ______.

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