Oh, dude, so like when you divide 640 by 30, you get 21 with a remainder of 10. It's like when you're sharing a Pizza and you're left with those last few slices that no one wants to touch. So yeah, 21 pizzas for everyone, and you can fight over who gets that extra slice.
23.7037
640 divided by 3 is 213 with remainder 1
640 divided by 8 is 80 with remainder 0.
12.7156
I will not answer since this is a question a teacher will ask you
21.3333
6.0667
7.5
15
3.75
30
30.4762