It is: 1
There is no whole number that goes into 980 evenly three times.
3
These do: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48.
3 and 1 will go into both number evenly leaving no remainders.
One.
1 and 3.
Either 2 or 3
37
3 goes into 36 and 63 evenly.
1, 3, 9, 27.
1, 3, 5, 15.
1, 3, 5 and 15.