Part 1. Definition
You are given a math word problem and you are supposed to apply an addition mathematical operator on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
Part 2. Example
Context: 21 children were riding on the bus. At the bus stop 5 children got off the bus while some more got on the bus. Then there were 16 children altogether on the bus. 

 Question: How many children got on the bus at the bus stop?
Answer: 0
Explanation: Number of children who got on -> 21 - 5 + x = 16 , x = 0, hence no one got onto the bus
Part 3. Exercise
Context: Robin's hair was 14 inches long. It grew by 8 inches. Then he cut off 20 inches. 

 Question: How long is his hair now?
Answer:
2