But an easier way for numbers like this, you say, hey, 13 is right exactly halfway between 12 and 14. So there you have it. I have the middle of the first half, this five. I have the middle of the second half, 13. To calculate the interquartile range, I just have to find the difference between these two things. So the interquartile range for this first example is going to be 13 minus five. The middle of the second half minus the middle of the first half, which is going to be equal to eight.