
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 number $a$ is represented by point $A$ on the number line. When point $A$ moves $6$ units to the left on the number line, it reaches point $B$. The numbers represented by points $A$ and $B$ are exactly the opposite of each other. Then the number $a$ is ______.

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