counter-clockwise
In mathematics counter-clockwise rotations are considered “positive”.
That clockwise rotations (rotations like the hands of a clock) are left to right is most likely due to the fact that a sundial (on the floor) in the northern hemisphere has a shadow that moves that way and the hands of the first clocks where simply made to mimick that movement.
In mathematics on the other hand, a positive rotation is the other way around. This could be a consequence of the fact that the movements of the stars (again in the northern hemisphere) are rotating counter-clockwise around the polar star–making that the prefered positive direction for mesuring angles which in turn gives a prefered rotation direction. (this was not only the best but also the only explanation I could find. And since mathematics has been astronomy for the most part of its existence I think it is quite likely)