How many $10$ digit natural numbers do not contain the digit $6?$ Numbers cannot start with zero.

How many values can the first digit take?

For each of those values, how many different numbers that do not contain the digit $6?$

Think of the different values each of the remaining digit can take.

The first digit can be 8 different options $($i.e. not $0$ and $6)$ and the rest can be anything but $6.$ The number of numbers without any 6s is $8 \times 9^9.$ (Note: We don’t expect you to calculate the final value!)