21.3333
640 divided by 30 is 21 with remainder 10
21 R3
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
7.5
30