1) Chiyo's mom is descended from Japanese nobility, which is where all the money comes from. Mrs. Mihama praises her husband as a "prince," "diamond in the rough," and similar as a playful emphasis on the fact that she actually fell for a pretty average guy; Chiyo took this and ran with it, which is why she holds her dad in such high regard.

2) Tadakichi also has a noble pedigree; his ancestors have been guard dogs for the family since the last years of the 19th century.

3) Chiyo's brilliance went unrecognized through elementary school because she got stuck with sucky teachers every year, all of whom were pretty much "phoning in" their lessons. Chiyo got ahead anyway by reading a lot. Then she took a competency exam in fourth grade, scored off the charts, and got her legendary five-grade jump.