You can think of negative numbers as cold numbers
and
positive numbers as hot numbers (like with temperature)
If you take cold air out of a room then the room will get warmer.
so
3 - - 5 = 3+5 = 2
also look at this pattern
3 - +2 = 1
3 - +1 = 2
3- 0 = 3
If I continue the pattern then,
3- -1 = 4
3- -2 = 5