
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]


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Given the universal set $U=\{1, 2, 3, 4, 5, 6, 7, 8, 9, 10\}$, sets $A=\{1, 3, 5, 8, 9\}$, and $B=\{2, 5, 6, 8, 10\}$,
(1) Find $A \cup B$ and $(C_U A) \cap (C_U B)$;
(2) If the "difference" of sets is defined as $A-B=\{x|x \in A \text{ and } x \notin B\}$, find the set $A-B$.

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