Subtract two.
13
There are infinitely many possible answers:add 8multiply by 2 and subtract 1multiply by 3 and subtract 10multiply by 4 and subtract 19etc are all possible rules.
10/14 - 9/14 = 1/14
14
Yes you can. The result will be positive 14.
14+14=28
(w + 2)(w - 7)
18
-4
-42
If you want to subtract a smaller number from a bigger number then just subtract. For example: 14 - 12 = 2 and etc. (more but it is going to be too long) 15 - 13 = 2 16 - 14 = 2