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.

Q: Bianca was organizing her book case making sure each of the shelves had exactly 8 books on it . If she had 5 shelves of mystery books and 4 shelves of picture books , how many books did she have total ?

A: 72
****
Q: In fourth grade there were 10 students at the start of the year . During the year 4 students left and 42 new students came to school . How many students were in fourth grade at the end ?

A: 48
****
Q: Fred has 5 yellow balloons , Sam has 6 yellow balloons , and Mary has 7 yellow balloons . The balloons cost 5 dollars . How many yellow balloons do they have in total ?

A:
18
****