00:01
The largest three -digit number should be a number where you can't make another three -digit number with it.
00:06
That is, if you add one to it, you would get a four -digit number.
00:09
Well, if you have nine and you add one, you get ten.
00:13
That is, a one -digit number into a two -digit number.
00:16
So, by that logic, if you have 99, there's three digits, all nines, and you add one, you get a four -digit number of 1 ,000.
00:26
Therefore, the highest three -digit number is 99...