Teacher: In this task, you're given five sentences, numbered 1 through 5. Your job is to generate a title for the story that makes complete sense. The title must be short, with less than three words, use simple language, and include the main topic of the story.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Sentence 1: Marcus needed clothing for a business casual event. Sentence 2: All of his clothes were either too formal or too casual. Sentence 3: He decided to buy a pair of khakis. Sentence 4: The pair he bought fit him perfectly. Sentence 5: Marcus was happy to have the right clothes for the event.
Solution: Marcus Buys Khakis
Reason: Marcus's reasons for buying khakis is established, followed by his purchase of them and reaction.

Now, solve this instance: Sentence 1: Mark decided he wanted to surprise his son with a cool gift. Sentence 2: He drew up plans for an excellent tree house to build in the backyard. Sentence 3: Mark got some friends together to build it all in one day. Sentence 4: When Mark's son got home from school, Mark showed him the gift. Sentence 5: The boy was incredibly surprised and thrilled at the amazing present.
Student:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
The Terrific Treehouse