
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 student was investigating the function $f(x)= \frac {x}{1+|x|}$ ($x\in \mathbb{R}$) and provided several conclusions:
1. The equation $f(-x)=-f(x)$ always holds for all $x\in \mathbb{R}$;
2. The range of the function $f(x)$ is $(-1,1)$;
3. If $x_{1}\neq x_{2}$, then $f(x_{1})\neq f(x_{2})$ must also be true;
4. The equation $f(x)=x$ has three roots in $\mathbb{R}$.
  
Fill in the correct serial number(s) of the true conclusion(s).

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