The probability of rolling a specific outcome on a fair six-sided number cube is given by the formula:

P(event) = 1 / total number of possible outcomes

In this case, we are interested in the probability of rolling a 6 first and then a 0.

Since the cube has six sides and each side has an equal chance of landing face up, the total number of possible outcomes is 6.

However, the cube does not have a face labeled as "0". If we assume that you meant to refer to the face labeled "1" instead, then the probability of rolling a 6 first and then a 1 would be:

P(6, then 1) = 1 / (total number of possible outcomes) = 1 / 6

Please clarify if you meant a different interpretation of "0" or if you have any additional information.