Margaret Ball: Mathemagics

Just because mild-mannered suburban mom Riva Konneva was a warrior woman from an alternate reality didn't mean she got out of going on school field trips. Nor could she just slash and hack her way through parent- teacher meetings, as she earnestly desired when confronted with administrators who claimed that her daughter belonged in a program for the emotionally disturbed because she showed too much initiative and read ahead of the class. Riva had moved to the Planet of the Paper-Pushers to give her daughter the kind of education she, a simple girl from the mountains, never received, and now she was going to have to learn a whole new way of fighting... with paper.

On the other hand, when old enemies from her home universe track Riva down and attack her daughter, paper just isn't enough...