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: Carol was sending out birthday invitations to her friends. Each package of invitations she bought had 3 invitations in it and she bought 2 packs. If she wants to invite 9 friends

Question: How many extra invitations will she need to buy?
3

Context: After a typhoon, 2 trees in Haley's backyard died. If she had grown 12 trees initially

Question: How many trees does she have left?
10

Context: In a school there are 868 girls and the rest are boys. If there are 281 more girls than boys

Question: How many pupils are there in that school?
1455