We have a range that this thing can take on now of four, while the range for each of these was just two. Or another way you could think about it is these upper and lower ends of the range are further from the mean than these upper and lower ends of the range were from their respective means. So hopefully this gives you an intuition for why this makes sense. But let me ask you another question. What if I were to say, what about the variance, what about the variance of X minus Y? What would this be? Would you subtract the variances of each of the random variables here?