
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 certain school selects $3$ students from $5$ students to participate in a labor skills competition. It is known that among these $5$ students, there are $2$ students from the first year, $2$ students from the second year, and $1$ student from the third year. The probability that the selected $3$ students are from different grades is ____. Let the number of first-year students among the selected $3$ students be $X$. The mathematical expectation of the random variable $X$ is $E(X)=$ ____.

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