2582. What characters can be added here so that each character contains a part of the previous character? a) 計 -> _ -> _ -> 念 b) 針 -> _ -> _ -> 財

a) 計 -> 古 -> 吟 -> 念  

計  KEI, haka(ru), haka(rau) - plan, total, measure

古  KO, furu(i) - old

吟  GIN - sing, chant, recite

念  NEN - thought, concern

b) 針 -> 古 -> 員 -> 財  

針  SHIN, hari - needle

古  KO, furu(i) - old

員  IN - member

財  ZAI, SAI - money, wealth, property