洗发水每瓶15元,商场开展促销活动,买4瓶送1瓶,1次买4瓶,每瓶便宜多少钱?
120-70= 370+90= 350+80= 910-50= 560+40= 650-70=
27+67= 10×6-8= 39-0÷10= 88-23= 45-5×9= 25+0÷5=
77+93= 15×1-7= 39-100÷10= 99-77= 23-3×7= 35-35÷5=
45+28= 5×6-18= 38-0÷5= 98-23= 100-10×10= 67+10÷5=
33+67= 5×6-0= 59-0÷10= 56-0= 9-9×0= 25+40÷5=