Double Digit

Monaghan, Annabel. Double Digit (Digit #2)
January 7th 2014 by HMH Books for Young Readers 

Digit is off to MIT and gets off to a good start; she finds a group of hackers on her floor, her roommate is awesome, her RA is kind of hot and works for the professor whose work enthralls her, and John is willing to visit with her on weekends. However, when he visits the first time, he tells Digit that she needs to have the full college experience, which she won't have if she keeps visiting with him. Fresh from her broken heart, Digit tries to throw herself into her work with a professor, and ends up hacking into the Department of Defense to get information for which she has clearance. It's all an issue of timing, she insists: if she had to wait around, she would be late for a toga party. Several people have been watching her every key stroke, so this little incident brings her to the attention of not only John's father, but the evil Jonas Furnis. John and Barbie-like agent Spencer come to relocate her, but instead Spencer works for Furnis and take her (along with her visiting brother, Danny) off to a remote farm from which Furnis hopes to bomb New York City in an effort to convince the US to start living in harmony with the earth. Once again, only Digit can save the world from a certain apocalypse. Once she does, she returns to MIT to check in with her parents, fight a bit with John, and manage to get into yet another critical situation from which she can escape only by using her mad code breaking skills.
Strengths: It's SO hard to find books set in college for middle grade readers, but this one does a great job of using innuendos about Digit and John's relationship, and being mercifully clean when it comes to language. This series is an absolute must if you have a fan base for Ally Carter's Gallagher Girls series. It's also a great book for showcasing a girl with awesome math skills.
Weaknesses: The back and forth with John about whether they should date or not gets wearisome. After all, Bass is a cutie, smart, and seems to like Digit. Romantic tension, I guess, but not my favorite.

N.B. Rare instance of a cover change for the better; unfortunately, I have the first book with the original cover.