
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 person uses an unequal-arm balance to weigh a block of iron G. When the block is placed on the left pan of the balance, its mass is measured to be 0.4 kg; when placed on the right pan, its mass is measured to be 0.9 kg. Find the actual mass of this iron block.

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