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.

Context: Every day Ryan spends 2 hours on learning english, 5 hours on learning chinese and 4 hours on learning spanish. 

 Question: How many more hours does he spend on learning chinese than he does on learning spanish?
1

Context: Paco had 97 salty cookies and 34 sweet cookies. He ate 15 sweet cookies and 56 salty cookies. 

 Question: How many sweet cookies did Paco have left?
19

Context: Paul got a box of 521 crayons and 66 erasers for his birthday. At the end of the school year he only had 154 left while not having lost a single erasers. 

 Question: How many crayons had been lost or given away?

367