18 19

18 19 18 19 18,19 18 19 18,19, 18,19, 18 19 18,19, 18 19 18 19 18,.19, 《9+19/18》×《 -19》 (9+18/19)×(-19) 19又18/19等于? 17,18,19,20 数学题17-18-19 17 18 19 16 17 18 19