In a decimal number, a bar over one or more consecutive digits means that the pattern of digits under the bar repeats without end.
Thus, in the given where 6 has a bar above, it is also equivalent to 0.66666..... with 6 repeating to infinity.
That decimal is equivalent to 2/3.
Since there is a negative sign, it also became a negative number.
Therefore, the answer is:
It is -2/3.