If you roll a dice six times, what is the probability of rolling a number six?

There is a 66.5% chance of it landing on a 6 at least once.
Because there are six faces on a die, you have an even chance of the dice landing on one of these faces each time you roll: $\frac{1}{6}$. This means that each time that you roll, there is a $\frac{5}{6}$ chance that you will not roll a 6. The probability of not rolling a 6 twice is $\frac{5}{6} \cdot \frac{5}{6}$, or 69.4%.
Roll the die six times, and the probability of not rolling a 6 is $\frac{5}{6} \cdot \frac{5}{6} \cdot \frac{5}{6} \cdot \frac{5}{6} \cdot \frac{5}{6} \cdot \frac{5}{6}$, also written ${\left(\frac{5}{6}\right)}^{6}$, which = 33.5%. Therefore, the probability of rolling a 6 at least once in 6 rolls  = 100%-33.5% = 66.5%