John would like to get Mary better. They are taking a class together right now, and John thinks he would like to hang out with Mary another time. Unfortunately, John is male and Mary is female, which presents a language barrier. He has tried finding her on Facebook, but alas, she doesn't have an account. What he would like is her phone number, so they can keep in touch after the semester is over. The problem is that if he asks the simple question, "Can I have your phone number," Mary will probably interpret it as "I think you are attractive—would you like to go on a date sometime?" That is not what John wants to ask. (Actually it is, but he's afraid to ask it.)
So John resorts to subterfuge. He asks for everyone to exchange phone numbers in his study group, just in case he's late and he needs to call someone. Not that he's going to be late. He just wants to be safe. Then, he thinks of an excuse to call her. An hour before class, he finds that he doesn't know what the homework assignment is. So he shoots a text over to Mary: "did you catch what the homework assignment was for today?" She texts back: "Yeah, but it's kind of long." So he calls, chats for a minute, gets the assignment, and voila! The two have exchanged phone numbers.