The Interstellar Arithmetician

A thousand-year-old Imperial Preceptor transmigrates to the interstellar age after dying, only to become a good-for-nothing! The Imperial Preceptor isn't fazed. What's so scary about being a good-for-nothing? She'll just refine a few batches of pills, and even a good-for-nothing can become a genius.

But could someone please tell her why the plants in this era not only release poisonous mists but also bite people, and why there's a bunch of violent girls who treat mechs like toys and smash them to pieces? The stars are way too dangerous. She wants to go back to Earth!

P.S. The title has little to do with the story. I just made it up on a whim, so don't ask.