That would be the lowest value that you could take on. And what would be the highest value? Well, the highest value is if you have a high X and a low Y, so 17 minus three is 14. So notice, just as we saw in this case of the sum, even in the difference, your variability seems to have increased. This is still going to be, the extremes are still further than the mean of the difference. The mean of the difference would be 16 minus four is 12. These extreme values are two away from the 12.