Answer:
Find the median (the middle number).
Find both the upper and lower quartile.
Then subtract the upper quartile from the lower quartile and you get the fianl answer.
For example:
1, 12, 16, 23, 34, 54, 72
median: 23
lower quartile: 12
upper quartile: 54
(IQR) interquartile range: 54 - 12 = 42
We get the interquartile range of 42.
