How to send text messages to classmates who haven't contacted for a long time?

Say something formal first ... like "Hello, guess who I am?" "Do you know who I am?" Knowing that the possibility that the other person will guess you when he sees a strange number is zero, but in this way, he can open a gap, find a reason to chat, and then recall what happened in junior high school with her. Next, my friend, it's up to you ...