Teacher: 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.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Context: Sam is 6 feet tall and Alex is 5 feet tall 

 Question: By how many feet is Sam taller than Alex? 
Solution: 1
Reason:  Sam's height - Alex's height = 6-5 = 1

Now, solve this instance: Context: They decided to hold the party in their backyard. If they have 5 sets of tables and each set has 10 chairs 

 Question: How many more chairs than tables do they have?
Student:
45