@Metasepia
I know right??? This one is unlike those wannabe chaotic mangas with supposedly "slow life" on their titles that just immediately turned out to be bull because the MC managed to get too much unwanted attention right off the bat in the first to 3rd chaps unlike the little guy here who is just pulling out small "tricks"(which really, is just some common little things from his previous world) verryy slowly that would solely remain inside the fief. Hopefully this would remain consistent as much as it allows to be.
@flannan
frankly I don't remember about earlier chapter
but AFAIK you only studying addition or math in general in elementary school, before that it just studying alphabet and numbers