
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 bag, there are $4$ red balls, $m$ yellow balls, and $n$ green balls. Now, two balls are randomly selected from the bag. Let $\xi$ be the number of red balls selected. If the probability of selecting two red balls is $\frac{1}{6}$ and the probability of selecting one red and one yellow ball is $\frac{1}{3}$, then $m-n=$____, $E\left(\xi \right)=$____.

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