
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 a certain kingdom, numbers are expressed in base $r$. A person buys a car for 440 monetary units (m.u.) and gives the seller 1000 m.u., receiving 340 m.u. in change. Calculate the value of $r$.

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