Teacher:You are given a math word problem and you are supposed to apply multiple mathematical operators like addition, subtraction, multiplication, or division on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
Teacher: Now, understand the problem? Solve this instance: sean is playing monopoly with his friends . he already has 27 houses . sean traded in 8 houses for money to buy park place . he collected so much rent that he decided to buy 12 more houses . how many houses did sean have then ?
Student:
31