The answer is four. You don’t have to move the three math books anywhere. You simply have to move the four science books around the three math books which are kept together as a single unit. And you move the science books around the math books one book at a time.
The answer is four. You don’t have to move the three math books anywhere. You simply have to move the four science books around the three math books which are kept together as a single unit. And you move the science books around the math books one book at a time.