00:01
I think what i would do is start with any numbers that start with a 3.
00:07
And i guess what you have to realize is it could start with 300.
00:13
So these numbers don't actually matter.
00:15
But what we have are 10 options here about this.
00:22
So there's only one way to start with a 3.
00:24
But you have 10 options for this, 10 options for this, and 10 options for this.
00:29
And as i multiply those together, it's the fundamental counting principle, you get 1 ,000 ways of doing that.
00:37
But then if we do it kind of the other way, where we could end with a 3, i guess what i'd be thinking about, if i start with 1 ,003, 1 ,013, and start counting all the ones that end in a 3, i guess what i'm thinking about is that 1 ,000 through 1 ,100, how about this, 1 ,093, has 10 options there.
01:14
But then we also need to do that for all of these numbers.
01:20
We could change all those...