1879. What character can be added to both of these characters to give other characters? 加_ -> _才

Answer:

加  KA, kuwa(eru), kuwa(waru) - add, append, join, take part

才  SAI - talent, genius

Add 木:加+木 木+才 

木  MOKU, BOKU, ki - tree

架  KA, ka(keru), ka(karu) - hang, build (a bridge)

材  ZAI - wood, material