-2835
406 times.
-156
7 can be subtracted from 49 only one time.
It is 9 times when it is subtracted from 42 and until reached 0
-1064
0.58 subtracted by 7 = -6.42
7N - 4N = 24
1.5 subtracted from 8.5 is one of infinitely many possible answers.
21
7 hours subtracted by 30 minutes = -23
13
-104
1, 2, 4, 7, 14, 28 1, 2, 3, 6, 7, 14, 21, 42 1, 2, 4, 7, 8, 14, 28, 56 And just in case: 1, 2, 7, 14, 29, 49, 58, 98, 203, 406, 1421, 2842