Tensai means genius, but sai also means "-years old." And I'm leaving the joke untranslated because it's after midnight and I can't think of a good localization.
将来
偉
Title: "Tensai"
1.
Tomo: "You seem like you'd have a pretty bright future since you're a genius, Chiyo. When you make it big some day will you take me out for crab?"
Chiyo: "I haven't decided what I want to be when I grow up yet."
2.
Yomi: "If she makes it big, do you think she's going to associate with the likes of you?"
Tomo: "Is that true, Chiyo-suke? How heartless!"
Chiyo: "That's not true..."
3.
Osaka: "That ain't right..."
Osaka: "Chiyo-chan ain't a tensai no more..."
4.
Osaka: "She turned 11, so now she's a one-teen-sai."
Yomi: "I think you mean 'eleven'..."