Teacher:Given a math word problem, answer the following question. You might need to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the question and then only report the final numerical answer.
Teacher: Now, understand the problem? Solve this instance: 29 birds were sitting in a tree . some more fly up to the tree . then there were 42 birds in the tree . how many more flew up to the tree ?
Student:
13