We really can not prove why any creature evolved the way it did since we can't demonstrate evolution in the lab. I have seen speculation but like most things in this field it is nothing more then that and there is not reason why an expert’s speculation would be better then mine or maybe even yours.

There is no real difference in simple math and girls do as well if not better then boys at arithmetic and multiplication. They also do well in some complex math things like geometry proofs. It is the higher levels of math where the real differences show up and the higher you go the bigger those differences become.

The best theory I have seen is the only real difference comes in with spatial thinking. We know that men and women even seem to navigate differently with women using land marks and men more often relying on maps in their heads. In a hunter gather society where weak little humans were hunting things like mammoth and wooly rhinoceros there would have been enormous evolutionary pressure to be good at since being bad got you killed and your kids starve.

If you assume males were the primary hunters (and only screwball left sociology professors try to argue otherwise) then the ability to handle spatial issues would help the males much more then it help the females. The females were more likely to travel shorter distance and since they were aiming for stationary targets they would have been more likely to return by the same path. Land mark navigation.

Males on the other would have traveled much further to find animals then follow them looking for opportunities to pick off weaker straggles from a large herd. Once they started hunting they would have used multiple men driving the animal to a desired location to kill it. That requires spatial skills to both plan and execute, be in the wrong place and your trampled, let it get away and your status as a hunter drops. Once you attack spatial skills come into play with angles of attack and such.

Like I said that is all just a theory and unprovable since we don’t even know how they hunted but it does give a viable explanation.