instruction:
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.
question:
Context: Tiffany was collecting cans for recycling. On monday she had some bags of cans. The next day she found 4 more bags worth of cans. If she had a total of 8 bags altogether 

 Question: How many bags did she have on monday?
answer:
4


question:
Context: Kelly has 80 nintendo games. She found 31 more nintendo games. 

 Question: How many does she need to give away so that she will have 6 games left?
answer:
105


question:
Context: There were some roses in the vase. Jessica cut 16 more roses from her flower garden and put them in the vase. There are now 23 roses in the vase. 

 Question: How many roses were there in the vase at the beginning?
answer:

7