
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
Given an equilateral triangle ABC with side length $2 \sqrt {3}$, and a point M in the plane of triangle ABC satisfies $\overrightarrow {CM}= \frac {1}{6} \overrightarrow {CB}+ \frac {2}{3} \overrightarrow {CA}$, find $\overrightarrow {MA}\cdot \overrightarrow {MB}$.

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