Just for convenience, let's say that North is the positive direction.
Then it must follow that South is the negative direction.
Vector A is a vector in the positive direction with a magnitude of 2 .
Vector B is a vector in the negative direction with a magnitude of 5 .
When they're subtracted, A-B is ( +2 ) - ( -5 )
= ( +2 ) + ( +5 )
= +7 .
The vector (A-B) points North and has a magnitude of 7 .