二一添作五 [ㄦˋ ㄧ ㄊㄧㄢ ㄗㄨㄛˋ ㄨˇ; er4 yi1 tian1 zuo4 wu3] lit. one half equals zero point five (division rule in abacus reckoning) to share fairly between two parties to go fifty-fifty ◄ ►