食杂店运来42箱矿泉水，卖出18箱后，又运进9箱，现有多少箱矿泉水？.p9](j.j'E-m+T0z4t'D
算式：提示.|*s,c2A+c*w5X3J.p9](j.j'E-m+T0z4t'D
答；现有7m9}8B(S-_1a2E1p箱矿泉水。.p9](j.j'E-m+T0z4t'D