Find the range, the quartiles and the IQR

Numbers of leaves on young plants were recorded as follows

4 leaves, 4 leaves, 6 leaves, 12 leaves, 12 leaves, 13 leaves, 19 leaves, 20 leaves, 21 leaves, 31 leaves

Use the median-of-halves convention: order all observations, retaining repeats. If the number of observations is odd, omit only the middle observation from both halves. Q1 and Q3 are the medians of the lower and upper halves