00:01
Okay, so let's start by evaluating 18 minus 6.
00:04
That's a 12 factorial.
00:06
So we can rewrite this as 18, 17, 16, 15, 14, 13, and then 12 factorial.
00:16
Divide that with 6 factorial and 12 factorial here.
00:19
We can cancel out our 12 factorial.
00:22
And now 6 factorial, well, that's 6 times 5, 4, 3, 2, 1.
00:31
So what can we do? well, 15 is 5 times 3...