Oh, dude, let me do some quick math for you. So, 13 goes into 21 like, once. Yeah, that's it. Just once. It's like when you try to fit into your high school jeans - it's a tight squeeze, but it technically works.
34 times with a remainder of 13
13 times.
13/x times.
21 times with a remainder of 7
Exactly 13 times
It goes: 1008/21 = 48 times
21 times, remainder1
13 times
13 times with a remainder of 13
5.4 times
2.625 times.
21 times.