TASK DEFINITION: You are given a math word problem and you are supposed to only use subtraction on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
PROBLEM: Context: Paco had 40 sweet cookies and 25 salty cookies. He ate 28 salty cookies and 15 sweet cookies. 

 Question: How many more salty cookies than sweet cookies did he eat?

SOLUTION: 13

PROBLEM: Context: Jessie weighed 71 kilograms. After she started to go jogging everyday she lost 20 kilograms. 

 Question: How much does she weigh now?

SOLUTION: 51

PROBLEM: Context: They decided to hold the party in their backyard. They have 10 sets of tables and each set has 6 chairs. If there are 11 people sitting on chairs 

 Question: How many chairs are left unoccupied?

SOLUTION:
49