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.

Example Input: the book fair had a sale where 3 books were $ 18.72 . if you wanted to buy 6 books how much money would you need ?
Example Output: 37.44

Example Input: jane helped her mom prepare fresh lemonade . if each glass needs 2 lemons how many glasses of fresh lemonade can she make if they have 18 lemons ?
Example Output: 9

Example Input: a worksheet had 4 problems on it . if a teacher had 9 worksheets to grade and had already graded 5 of them how many more problems does she have to grade ?
Example Output:
16