Answer :

Step 1: Put the numbers in order.
1,2,5,6,7,9,12,15,18,19,27Step 2: Find the median (How to find a median).
1,2,5,6,7,9,12,15,18,19,27Step 3: Place parentheses around the numbers above and below the median. 
Not necessary statistically–but it makes Q1 and Q3 easier to spot.
(1,2,5,6,7),9,(12,15,18,19,27)Step 4: Find Q1 and Q3
Q1 can be thought of as a median in the lower half of the data. Q3 can be thought of as a median for the upper half of data.
(1,2,5,6,7),  9, ( 12,15,18,19,27). Q1=5 and Q3=18.Step 5: Subtract Q1 from Q3 to find the interquartile range.
18-5=13.
Hope this helped:) 
-BRIEMODEE:)