
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
At the dining table, every dish and grain of rice, every sip and toast, are not easy to come by. The waste of food on the tip of the tongue is shocking. According to statistics, the total amount of food wasted in China each year is equivalent to about 500 billion kilograms. $500$ billion can be expressed in scientific notation as ____.

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