
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
Observe the following equations: $1=1^{2}$, $1^{2}-2^{2}=-3$, $1^{2}-2^{2}+3^{2}=6$, $1^{2}-2^{2}+3^{2}-4^{2}=-10$. According to this pattern, the 100th equation $1^{2}-2^{2}+3^{2}-4^{2}+...-100^{2}=$ \_\_\_\_\_\_.

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