The number is 112 and its multiples.
The number that both 7 and 8 can go into evenly is 56.
7 and 31 go into 217 evenly.
Only the number one (1).
The number 7
168
Just 1.
It is: 252
1, 7, and 49.
3.5 you multiply it by 2
It is: 210
Just 1.
They will all divide into 280 evenly with no remainder