倒ㄉㄠˋdào數ㄕㄨˇshǔ

逆數，從後往前數。如：「飛彈發射前，倒數計時」。

英to count backwards (from 10 down to 0), to count down, from the bottom (lines on a page), from the back (rows of seats), inverse number, reciprocal (math.)

法inverse

德Kehrwert, reziproker Wert (S)