3-4
If you think about this on a number line, it isn't too hard.
So picture a line with negaitive numbers on the left going to positive numbers on the right. Something like this...
-5 -4 -3 -2 -1 0 1 2 3 4 5
So you want to start and the positive 3 and go to the left 4 numbers...
There's your answer. :]