Bella bought stamps at the post office. Some of the stamps had a snowflake design, some had a truck design, and some had a rose design. Bella bought 11 snowflake stamps. She bought 9 more truck stamps than snowflake stamps, and 13 fewer rose stamps than truck stamps. How many stamps did Bella buy in all? Let's think first. Chain of thought:
The number of truck stamps is 11 + 9 = 20. The number of rose stamps is 20 13 = 7. Bella bought 11 + 20 + 7 = 38 stamps in all.
Therefore, the answer is 38.