00:01
Okay, so how many digits do i have? well, i have zero, one, two, all the way up until nine are my digits, and there's a total of ten digits.
00:09
Okay, suppose i want eight digit numbers.
00:12
So one, two, three, four, five, six, seven, eight.
00:18
Okay.
00:19
So the leading digit cannot be zero.
00:22
So the first digit can't be zero.
00:23
So it could be one, two, three, four, five, six, seven, eight, or nine.
00:25
So i have nine choices.
00:27
And the last digit cannot be one...